Hydronic Heater Installation - Separate H2O heater from FWC System?

[wurzner]

I currently have my hot water heater patched into the fresh water side of my engine and am planning to put in a Espar Hydronic D5. At this time, I'm considering plumping it so my radiators will have the ability to heat the boat (and H2O heater) when motoring using engine heat or the diesel heater. The downside is if anything breaks in the circuit, I lose my freshwater cooling. The other option is plump my H20 into the hydronic an completely separate both circuits.

I like option one in the sense that I have the option of heating the boat when motoring or running the diesel heater. I don't like the fact that if any part of the circuit fails...I'm screwed. The third option is to plump them all together, and have 2 three way valves to eliminate the H20 and heating system in the event of a leak.

Anyone want to contribute some workds of wisdom? As usual. I'm willing to pay the equivlent of Loren's consulting fees of 02 cents to anyone who requires compensation.

Thanks to Craig and Ellen on Pilot Project for letting me take photos of their installation...it will sure help me out in the long run.

regards
shaun
S/V Sorcerer
Ericson 38-200 1986

 

[Carson Reed]

Play it safe

I would definitely opt for the 2 3way valves, myself, as it's pretty cheap insurance. If something can go wrong someday, it will. Maybe even sooner than later, as the bugs get worked out of the new system.

 

[Trucker Doug]

I'll second the 3 way valves. But 2 sets. Even the hot water heater sould be able to be bypassed somewhere close to the engine. That way when it all goes wrong, you have options (and unused hose to rip off of something to make repairs.)

 

[Cory B]

2 Systems w/heatExchanger

We're hoping to add a hydronic system someday ourselves. I'm thinking we may go with 2 separate cooling systems, but have a heat exchanger between them so the engine system will still be able to pull double duty and heat the boat on long runs. Maybe the best of both worlds?

- Cory

 

[footrope]

We recommend instant hot water

Shawn,

We were happy to let you and Dick see the installation on the 'Project last weekend. We elected not to connect the engine coolant system to the Espar system in any way, but it was tempting to do so. That is a tough decision, but we decided to run the Espar if we wanted cabin heat while underway. I forgot to give you the nickel tour of the triangle tube heat exchanger we installed in the Espar coolant circuit, so I'll take this opportunity.

While we initially considered hooking the Espar to the coolant loop on the water heater, we changed our minds. But, we do use the Espar to provide instant hot water through a coolant-to-water heat exchanger. It works great and it only takes 10 minutes warm-up. In addition to the heat exchanger, we had a mixing valve installed to allow us to set the max temp coming out of the instant system to prevent scalding - the coolant is heated to 180 deg F and the heat exchanger is very efficient. We also avoided adding complexity in the engine cooling circuit.

The pictures I have attached are hard to make sense of, so I'll describe what we did.

1. We did not disable or change the engine coolant circuit, so we still use the engine coolant to heat the water in the hot water heater when the engine is running.
2. The PO installed a 12 gallon water heater and that was a factor in our decision. The engine loop in the water heater is a simple U, I think, not very efficient. Our hot water lasts about 12-24 hours after engine stop. The bigger factor was avoiding the extra valves and the potential to add complexity (failure points) to the engine coolant circuit.
3. The triangle heat exchanger was put at the output of the hot water heater - this is the only location it can go if you want instant hot water from a cold hot water tank. The triangle heat exchanger fits easily atop the hot water heater.
4. The Espar coolant side of the triangle heat exchanger was placed after the output of the last cabin heater in the Espar circuit. So, cabin heat is the first priority, and water heat is the second priority. It's always inline. No valving is needed to activate it.
5. The mixer valve (with the grey knob, up-side down) is in the output of the fresh water side of the triangle heat exchanger.

We even have the forward head/shower location and believe me, the water's fine! I hope this helps. You can contact me back channel for more and we can do another visit, if needed. Do a search on hydronic - I think I posted a schematic of the system in a thread on my hydronic vs. forced air decision from 2005.

 

[CaptnNero]

Valve pm

Just make sure to exercise the valves periodically so they'll work when you really need them. Besides regular p.m., I use the old guideline for seacocks, "if you see them, cycle them".

The third option is to plump them all together, and have 2 three way valves to eliminate the H20 and heating system in the event of a leak.

 

[stbdtack]

Another option: Isotemp offers their water heaters with dual heat exchangers. So the Espar can have its own circuit in the water heater.

Although not the most efficient method, the engine warmed water in the hot water heater can heat the Espar circuit to provide some heating when just using the engine. They also are the best water heaters around. Mine will still have warm water 3 days after its turned off.

Be careful about adding anything in the engine fresh water cooling circuit. Unless you have done the hot water heater bypass fix (detailed on this board), you can slow the the coolant flow enough to have overheating problems.

Good luck

 

[Starrnet]

Plumbing Options

Shaun,
I diagramed the options and, as you know, both work. Simple is nearly always better. The complexity of joining the plumbing of both systems is something you don't need. It is noisier, but you can gain some downside heat by opening the engine hatch while underway. If you are trying to keep your crew warm while racing and you have the engine running, that is a confession!

The biggest problem with the instal of the hydronic system is running the hoses to the radiators. I am considering abandoning the instal after three routings proved impossible because the hoses cannot be routed to the starboard radiator. If you advise anyone on the instal, be sure to tell them to solve the hose routing FIRST, even before buying the system.
Dick Starr