Espar hydronic heating system

[matts997]

Looking for some help understanding the hydronic heating system on a new (to me) sailboat, a 2018 Marlow 31 (with a Yanmar 3YM30AE & SD25 sail drive). I’ve owned the boat for less than a month and I’ve not had a diesel heater on any previous boat.

After working well 2 or 3 times, the Espar (D5, 12 V) failed to start up, making a weird grinding noise and emitting a hot, burning smell--so I shut it down immediately. I discovered the coolant expansion tank for the heater was completely empty, as was the expansion tank for the engine radiator (don’t know if these are directly related??). I found traces of leaking coolant just below the Espar main unit, so I’m thinking the system didn’t start because there wasn’t enough coolant. I tightened every hose clamp I could find—assuming this was the cause of the leaked coolant--and my plan is to fill both expansion tanks to the half-way point and then try starting the heater again.

Before I do that, is there anything major I’m missing here? I don’t fully understand the interactions among the two coolant systems (heater and engine) and the hot water heater....e.g., when motoring with the furnace off, does the engine heat the coolant in the heating system as well as the hot water heater? Is there a heat exchanger somewhere in the system?

If anyone can point me to an article or video that would be great. The Espar owner’s manual isn’t very helpful.

Thanks,
Matt

 

[dlochner]

The Espar and Webasto heaters were designed to keep truckers warm when sleeping in cold environments and to preheat cars in very cold environments, you won't find much information from either company on how they work on boats.

Without a whole lot more information on how your system is set up, it is difficult give any definitive answers on your problem. With that said if the expansion tanks are empty you have a problem. There should be coolant in both. There should be a drain on the hydronic system that will allow you to drain and flush the system. Then it needs to be refilled with an antifreeze/water solution and corrosion inhibitor. The system will also have to be bled to remove air from the system.

Likewise, the engine freshwater cooling system should be drained, flushed, and refilled with an appropriate antifreeze.

It is unlikely that the problems are related other than from a lack of maintenance by the prior owner. There is a way to use engine heat to heat the hydronic system, however even doing that the coolants shouldn't mix, so a leak in one should not affect the other.

Sure Marine in Seattle are experts in hydronic heating, I don't know if they do service calls.

 

[matts997]

Thanks for confirming that the engine and heating cooling systems shouldn’t mix, probably function independently.

The previous owner had the local Yanmar dealer do a full 5-yr maintenance service in October before the boat was sold, including draining/flushing both the heater and engine cooling systems. The Yanmar tech found a couple leaks in the heater loop hoses, but they apparently repaired those and bled and pressure tested the system. That was ~ 20 engine hours ago.

The problem is I don’t know exactly how the system was installed & set up....I’ve got a few guesses based on inspection, but I'm just not certain. e.g., there are 3 ball valves under the port settee and a toggle switch in the lazerette next to the Espar main unit, the purposes of which are unclear to me (images below, toggle switch circled in red). So I might have to get a HVAC tech to help me figure that out. Or talk to whoever originally installed the system when the boat was new, if I can locate the shop.

FYI, I talked to Sure Marine last week and they now only work on Webasto. And the shop that does handle Espar in Seattle no longer provides direct service.

 

[Mark Maulden]

The espar guys in Seattle are AMC Cliff’sV Marine. Used to be Boat Electric but they disappeared. Sure Marine is the Webasto dealer. They all work the same. You should be able to energize the water pump only to fill and bleed the system. Start there.

 

[jssailem]

1. I don’t fully understand the interactions among the two coolant systems (heater and engine) and the hot water heater....e.g.,
2. when motoring with the furnace off, does the engine heat the coolant in the heating system as well as the hot water heater?
3. Is there a heat exchanger somewhere in the system?
4. I don’t know exactly how the system was installed & set up....I’ve got a few guesses based on inspection, but I'm just not certain.
5. e.g., there are 3 ball valves under the port settee and a toggle switch in the lazerette next to the Espar main unit, the purposes of which are unclear to me (images below, toggle switch circled in red).
6. So I might have to get a HVAC tech to help me figure that out. Or talk to whoever originally installed the system when the boat was new, if I can locate the shop.

Without specific information/instructions from the previous owner, I would need to develop a roadmap of the system. One place to start is the source to identify the system you have. Using your images and boat description, my guess is a Hydronic D5 unit from Espar.
See attached pdf. https://esparparts.com/productbrochures/Marine_Brochure_WEB_READY_021314.pdf

In dealing with a new to me preowned boat system, I would make a map and label all the system components. Hoses get labeled To= XXX From= XXX either on the hose or on a piece of paper that goes in my body system book.

Unless you trace the hoses from the engine/Espar unit to the valves/space radiators/ etc. it is only guessing what they do and how they are connected.

(1). I would start with a basic assumption, the hydronic unit was either a dealer installed option (for the PacificNW) or more likely after market Owner install. The work is neat so perhaps a professional install. Unless the owner specifically chose, my first thought is that the engine coolant and hydronic coolant are separate systems.

(2). If systems are independent - No

(3). Yes. The engine uses an HE (heat exchanger) to transfer heat from engine to raw water expelled with engine exhaust.
The Espar unit would use a HE to transfer the diesel made heat to the coolant and a HE would act like a radiator to transfer coolant heat to the air in the boat.

(4). draw a chart of the system/systems to give you the answer you seek

(5). The values control flow. I would guess from the D5 to areas of the boat for heating. Your hoses would take hot coolant from the D5 to a HE/radiator and return to the D5. Labels will help to remind which does what for crew. The switch location implies it controls electrical energy to something nearby ( my guess is the D5 unit perhaps a pump) trace the wires to see what is connected.

(6). yes. If you can not trace all the hoses and electrical lines then seeking help to do that work may be necessary. I would encourage you to do the tracing and recording of what you find. It would at the least be a start for the tech you hire. Otherwise you will be paying the tech to do all that discovery. The previous owner would be the first person I would call. He may be able to tell you who did the work.

Good luck. With heat you will be able to have an extended sailing season.

 

[dlochner]

After working well 2 or 3 times, the Espar (D5, 12 V) failed to start up, making a weird grinding noise and emitting a hot, burning smell-

How much fuel in the tank? Is the fuel drawn from the top of the tank or bottom? It is common and good practice for the heater fuel pick up to be several inches above the bottom of the tank, this prevents running the tank dry with the heater, leaving no fuel to start the diesel. The finding sound may be the heater fuel pump, it is likely a little piston pump and would make a clicking or grinding sound. If fuel is not getting to heater because the pick up is above the fuel level, the fuel line is clogged or the valve shut, the heater will not run. The start sequence should see the pump pumping fuel and the ignitor heating up. If the heater does not ignite the system will shut down.

 

[matts997]

Mark: I talked to Cliff at Cliff’sV Marine...he doesn’t provide any “on boat” service, but he gave me several suggestions on the phone (tighten all hose clamps, refill expansion tank and try to start it up again).

John:
-It is a D5 unit. Thanks for the Espar brochure link....I read it last week and it was the most helpful resource by Espar that I found. The layout in my boat is identical to the sailboat shown in the brochure’s diagram..i.e., main unit in the cockpit port locker with 4 heater fans, one each in the aft sleeping area, head, salon and v-berth.

-I’m pretty certain this was a professional install arranged by the broker who sold the boat new (and re-sold it to me). I’ve got a call into the brokerage to locate the installer and I can email the previous owner.

-Drawing a schematic of everything I can see is a great idea.

Dave: Good point about the fuel tank...right now the gauge is sitting half-way between 1/2 and 3/4s full. I’ll look for where it connects to thr tank.

Thanks everyone for the feedback/suggestions.

 

[dlochner]

Dave: Good point about the fuel tank...right now the gauge is sitting half-way between 1/2 and 3/4s full. I’ll look for where it connects to thr tank.

I would think that would be enough. Try priming the fuel line again. Remove the line from the heater, stick it in a bottle to catch the fuel and run the pump. See if you're getting fuel immediately or does it take a few moments? Once fuel is running cleanly, shut off the pump and quickly reattach it to the heater.

 

[Mark Maulden]

You also might try North Harbor Diesel in Anacortes. They actually replaced mine when I was under doc’s orders not to exert myself. They might even know of someone further south..

 

[Hello Below]

You should have a header tank in series with your hydronic coolant lines that looks something like this. Regardless it will have a pressure (radiator) cap on to of it.

When your system is cold, fill this tank with coolant then crack open the slotted plug located on top of your furnace until you get a steady stream of coolant. I can see the plug in your photo. This will bleed the furnace. (Note: During normal operation the header tank will self bleed the system so always keep that tank topped up. Also keep your recovery tank between low and full levels.).
The toggle switch electrically enables and disables your 4 HE fans. So in the summer when you turn the furnace on, you can heat your domestic water tank without cabin heat.
I cannot definitively state what the 3 valves do. I need to know where the red and black hoses go from the 2 lower valves. A picture would help. My guess is that 2 go to the engine and 2 go to water heater. The lower 2 valves work in tandem to select how you are heating your water (engine or Espar). The upper valve either puts the water heater tank in series or parallel with the Espar coolant. It is currently shown in the closed thus series state. For safety reasons, I leave mine open thus parallel.

 

[matts997]

Very helpful, thanks...I was really puzzled by that upper valve being in the closed position when the furnace had been working well the first few times I started it up. And the toggle switch...yes, that makes total sense....didn't know there was an option to heat the fresh water tank via furnace or engine.

I have the same header tank as the one shown in your image, which is full, it’s just the recovery tank that’s completely empty. But I will try opening the bleed screw as you suggest. Right now I’m waiting on the same extended life coolant/antifreeze that was most recently used to refill the system when it was drained and flushed out---had to order that online.

Mark--thanks for the North Harbor Diesel referral...I may have a good shot here of fixing this myself, but if not, I’ll give them a call.

By the way, I found this service manual for the Espar D5 (attached), which I had somehow missed before.

 

[dlochner]

it’s just the recovery tank that’s completely empty.

It is better to have some coolant in the recovery tank, but an empty expansion tank is a world of difference from an empty expansion tank. You might want to check the hose from the expansion tank to the recovery tank to make certain it is clear. This, however, does not explain why the heater was not igniting.

 

[Hello Below]

I was really puzzled by that upper valve being in the closed position when the furnace had been working well the first few times I started it up.

If the 2 lower valves are in the “engine position” and the upper valve is in the closed position (putting the water heater in series) as shown then there will be no coolant flow from the Espar coolant pump. An overtemp condition will occur and shut the furnace down. Do this too many times and the ECU will lockout any further attempts.

 

[matts997]

The furnace was used about 3 or 4 times before I discovered the closed valve. Don’t know who closed it and when, but from what you’re saying, this probably triggered the over-temp function, which then shut down the system when I last tried to start it up. Is this plausible, that it could have operated that many times (effectively) with no coolant from the Espar pump?

Does anything special need to be done to do a re-start after an over-temp shut down?

I feel like I’m very close to a solution here, thanks to everyone’s input.

Matt

 

[dkinzer]

there are 3 ball valves under the port settee [...]

I suspect that your installation has the valves to allow the Espar unit to provide heat to your water heater. My Webasto is not set up that way and there are only two valves that serve only to isolate the Webasto from the coolant loop that contains the small fan-forced radiators.

The valves you've shown look like 3-way valves and I understand that there are two types distinguished by the range of motion of the valve handle: 90 degree and 180 degree. The 90 degree type selects one side or the other to be connected to the middle. The 180 degree type does the same but also has an "off" position in which neither side is connected to the middle.

You'll have to trace out where the various hoses run in order to deduce how the system operates. I would suggest one of two possibilities: 1) the valve positions control whether the engine or the Espar provides hot coolant to the heating loop or 2) the valve positions control whether the engine or the Espar provides hot coolant to the water heater. I think that the latter possibility might be more likely because it would allow the Espar to heat your water while you're away from shore power.

 

[FastOlson]

I would first check/change out the little fuel filter that feeds the heater burner. Make (really) sure that the heater pump is receiving clean fuel with zero water. Water might get pulled in from low in the fuel tank, for instance. A clicking noise from the little fuel pulse pump should indicate that it's working, but might not. Best remove the hose from the pump outlet side and power up the pump, discharging fuel into a can.
I had a near-new furnace failure when the pump itself, against all apparent logic, failed to pump diesel. The pump is inexpensive, by boat standards, but the trouble shooting was not. (sigh)

 

[dkinzer]

After thinking about this some more, I suspect that the valves work as follows:

1) with the valves in the position shown in the photo, the heated coolant comes from the Espar on hose A which then runs to the small radiators throughout the boat, returning on hose C. It then flows through the Tee to the right hand 3-way valve and out hose E to the water heater and back on hose D. It then goes through the left hand 3-way valve, through the Tee and out hose B back to the Espar.

2) with the upper valve open and the two 3-way valves in the opposite position, the heated coolant comes from the Espar on hose A, through the radiator circuit and back on hose C, through the upper valve and out hose B back to the Espar. Meanwhile, heated coolant flows from the engine in hose F, through the left hand 3-way valve and out hose D to the water heater, returning on hose E, going through the right hand 3-way and back to the engine on hose G.

The actual direction of the flow might be the reverse of what I described but the paths I've described would allow either the Espar or the engine to heat your fresh water. If the fans on the small radiators are running, the cabin would be getting heated air via the Espar and with the fans off only a minimal amount of heat would be emitted.

 

[matts997]

dkinzer: Thanks for doing this--*very* helpful. I’ll be saving your edited image and text for future reference.

But if I’m understading you, these valve positions are unlikely to account for the problem I’m having (i.e., system won’t ignite after running well several times). Is that right? And with the valves in the positions shown in the image, is there still the possibility of an over-temp condition and automatic shut down/lock out, as Len described in a previous message?

I’ll take a step back and check out the fuel quality and the heater’s fuel filter, as FastOlsen suggests.

Failing that, it might be time to raise the white flag and get a marine HVAC tech to look things over.

Matt

 

[dkinzer]

these valve positions are unlikely to account for the problem I’m having

That is surely correct. However, the first step in diagnosing any system is to understand how it works. Be mindful that my description is only a guess at how the valves work but you should be able to confirm the guess based on which hoses run where.

We bought our 2007 H41AC two years ago and the Webasto furnace in it worked perfectly until after we returned from a three week trip to the San Juan Isands and back. It suddenly began failing to ignite and displayed a diagnostic code indicating that that was the problem. After taking the furnace apart and discussing what I observed with the techs at Sure Marine, I finally discovered that the burner needed to be cleaned. There is a tiny air passage that provides additional combustion air for the ignition process and that passage had become clogged with carbon. Although unrelated to the problem at hand, I also found a developing crack in the combustion chamber housing so I replaced that part since I had it disassembled. Upon reassembly, the furnace fired up right away but smoked a lot until it had burned out the excess fuel in the combustion chamber.

The techs at Sure Marine were a great help. This contrasts with a local shop that said that the unit was so old (probably less than 15) that it would be less expensive to replace it completely (at a cost of over $3000). It cost me less than $200 to get it running again and I now understand much better how it works.

 

[Bob S]

Matt,
I installed the same unit last season. I believe the manual says not to shut it down while it's in use. Like Dave said, these manuals are not very intuitive. I found reading the Hurricane manuals for their heaters the easiest to understand. It helped a lot with my install. I built a manifold as described. Made it easy to fill and bleed. Those valves are probably for a summer loop to heat hot water but not flow to the fan heaters. You really need to trace the whole system to figure out how it was installed in order to run it properly. I've attached how I plotted mine out. Good Luck!