Hydronic heating. cabin/water

[transmitterdan]

Dockhead,

Is there a good U.K. Distributor or one in Europe you can recommend? Our US parts supplier is pretty much useless.

[Dymaxion]

Hi, you show four heaters plus towel rack plumbed in parallel. It was suggested to put them in series instead. I would leave them in parallel and put in a control valve ahead of each one. There are a couple of reasons for this. First is that in series the flow resistance is larger than in parallel, secondly the first heater will take out the most heat etc until the last heater is passing cool water. Couple more are that you can balance heating in each zone by adjusting the valve, and if you want to you can add a zone control valve (4 zone) which listens to the thermostat in each zone and opens the corresponding solenoid valve. This way as zones heat up and close off flow the system gets to send "surplus" heat to the other zones for faster warm up. Plus you get to warm the main salon in daytime, then drop it down while raising temps in sleeping areas. Agreed, more complexity but this is exactly how house systems are plumbed and they are long lived. Just use a decent crimper on the pex tubing and insulate the outgoing runs to get maximum heat transfer at the air handlers. No point heating the contents of your bilge or whatever. Leave the return lines bare to extract last bit of heat on the way back to the boiler.

[Dockhead]

Originally Posted by transmitterdan

Dockhead,

Is there a good U.K. Distributor or one in Europe you can recommend? Our US parts supplier is pretty much useless.

Try these guys:

https://www.butlertechnik.com/

I've had good luck with them. Due to the decline of the pound, and the fact that you save VAT, it might even be cheaper to order from the UK.

[kristjan]

Maybe I missed it..but what is a good pump to use for coolant?
I have system of coolant goes through Dickinson stove two turns coil, then to plate heat exchange on engine coolant then splits in parallel to aft cabin radex and fwd cabin then rejoins and goes through 1200 watt 8 gallon quick hot water tank then to stove again. I have a “fill”that is low and before the pump and “vent” that is from high point, getting air out has not been an issue. But the Little magnetic 2.2gpm seems to be doing not even half that flow rate. I think because of system friction.
I don’t expect the hot water tank to heat the boat but just keep chill out when I am away for day and boat on shore power. Real heat will come from stove or engine when underway. Cheers.

[richwest3]

Just an update on the status of the system I installed (post #37): it's been two and a half years and I couldn't be happier. The system has been flawless with the exemption on the magnetic water pump that came with the Espar heater (to reply to the last post, that's what I used for a water pump). It went out about a year ago. I had an similar, extra magnetic pump that I used to use for my refrigeration. I installed that and it's been fine since.

Speaking of the coolant pump, I suspect that the little magnetic pump included with the heater wouldn't be powerful enough to move water through a large system. It system in entirely within the lazerette so the runs are short. The advantage of the included pump is that it's quiet and used very little power.

Sailorchic34 in post #29 calculated the heat output required and it was much higher than my little Espar's output. I think maybe the 2.2 gpm used in the calculation was way too high, or maybe it's just magic ;-) but our system works incredibly well. We have to mix in cold at the faucet to be comfortable.

We live aboard full time, southern winters in the tropics and Summers in New Zealand or Australia. The system has basically been used seven days a week. It's been working fine in both the temperate and tropical climates.

It was so cold in New Zealand when we left for Fiji this year that I installed a detachable "snorkel" so that we could use the heater for the cabin while underway without getting water in the exhaust.
I used a section of metal exhaust hose. That worked out fine.

After turning on the heater, we wait three minutes, warm the water in the pipes with a valve that runs the hot water from the shower back to the water tank (can't afford to waste water), and away we go. Knock on wood, we've had no problem with short-cycling. I do have to add a little coolant every six months or so.

The one small disadvantage we've found with this system is that when were in a marina, next to another boat with people on it, I worry about bothering them with the exhaust fumes and exhaust noise (we didn't install the supplied muffler). An apology in advance has always sufficed. (As you can gather from this, we don't use marina showers. We like ours too much!)

Another unconsidered disadvantage is that two people showering every day on the boat has been really hard on the wood in the head.

There's a link in my original post (#37) to our site with more details.

Thanks everyone for your inspiration and sharing your knowledge.

[GILow]

Thank you richwest3, it’s great when people come back and update us on these sorts of threads. I for one am going to go back and have a closer look at the details of your setup now.

[kristjan]

[kristjan]

[kristjan]

[kristjan]

I got my pump to work better, it had a small air lock I think. For the pics, the engine heat exchanger is off Amazon, the engine does a decent job of making the coolant circuit hot. It it takes a little while to happen. the hot water tank seems to add a few degrees but not too much ( I hope it just keeps some chill out when I am away) and I haven’t tried the two turn coil from the Pacific diesel stove yet but I expect it to be fine. There is a radex in aft cabin and radex in forward cabin that are in parallel in the circuit. The pic with that manifold is two valves to control flow through each of those legs and a by pass leg (with the ball valve) so I can use engine to heat circuit to make hot water but not send heat to the cabins.

[Dockhead]

Originally Posted by transmitterdan

Dockhead,

Is there a good U.K. Distributor or one in Europe you can recommend? Our US parts supplier is pretty much useless.

I've been using Heatso. https://www.heatso.com/


Butler is a great parts resource, and they have real people you can call who are knowledgeable.


https://www.butlertechnik.com/eberspacher-m1


They also have a lot of good technical information on their website.


Another fantastic technical resource:


Eberspacher

[Heath68]

Following...

[Dogscout]

Need to bring this topic back up.

I am planning on installing a Webasto Thermo Pro 90 in my boat this year. Along with the heater I will install 3 of the webasto whisperer heat exchangers which is a radiator with fan. I also already have a calorifier with elec. element and engine heat loop.

This thread has been very helpful although I have a couple of questions that I am hoping you all can answer.

I desire to heat the master cabin, salon and guest cabin so will be mounting a heat exchanger in each. I will plumb them in series but may use individual fan switches or potentiometers to control fan speed.

I desire hot water at the tap so I will tee this heater into the calorifier connection.

I will use engine waste heat as a primary source while motor-sailing, motoring, or recharging the batteries.

I do not see a need to warm the engine, but that may be a consequence of connecting to the existing calorifier loop.

Question; Do I need a separate header tank to allow for expansion? remember this will be connected to existing engine and calorifier loop. I believe that there is a header tank for this.

Question; would it be a good idea to isolate the cabin heating loop in the summer with isolation valves?

Question; Is teeing into the engine to calorifier loop a bad idea? EX: a leak in the cabin heating loop could go unnoticed and the engine coolant loss could be disastrous.

Thanks for all responses

[GILow]

I would not bother connecting to the engine. The Webasto is so fast and efficient that the gains from using the engine will be far outweighed by the extra complexity and potential for failure.

Plumbing the heaters in series is a bad idea, the third heater in the sequence will have very poor output, better to have them in parallel. Personally, I’d put a small pump on each heater to ensure adequate heat flow.

Potentiometer to control the fan speed is poor efficiency. Try PWM controllers instead. Just as cheap and much more efficient.

Are you planning to do the hot water the way described by Typhoon/ColdEh?

If the cabin heating loop runs from its own pump then the isolation is automatic. And certainly here in Australia I would want that isolation. John’s original design was for Canada where it may have been less of an issue.

[bcboomer]

I did something similar. My Planar diesel hydronic supplies the hot water plus a bus heater in the salon, plus some under floor heat under the table, plus a heated towel bar in the head. I plumbed mine in parallel and ran the supply and return lines through the storage spaces around the perimeter of the boat.
We have decent insulation in the aft cabin so body heat is more than enough there.
You definitely need to be able to turn down the heat in individual areas.
The major difference is that I put in a heat exchanger to pick up engine heat.
I was concerned about a leak in the heating system, which has a lot of connections, over heating the engine.
I'm not sure that parallel is necessary since sleeping areas really don't need much heat and, judging from my return line temperatures, there is still lots of heat left.
Hopefully your Webasto is more reliable than my Espar was. I've been really pleased with the Planar.