One Heater or Two?

[Paragon]

Dear Collective

I am looking to do a fresh install of a heating system in a 44' centre cockpit boat that will be used as a liveaboard. My favoured option is to go with a water based heating system rather than air and I am slightly drawn to Webasto rather than Eberspacher.

The question I am pondering is whether it would be better to have one central system (say Thermo 90ST) to do the whole boat or have two Thermo Top C's, one supplying hot water, aft cabin and perhaps galley and the other saloon and forecabin(s).

The positives as I see it of the single system are simplicity of installation and probably operation with the negatives being higher unit cost and no redundancy.

The positives of a dual system are much cheaper units, redundancy with the negatives of greater complexity of install.

I welcome your comments and perhaps there are things which I haven't even thought of that would negate an option.

 

[David2452]

Assuming you want to zone then a pair of TTCs would some kind of sense though it would not be my choice, a single thermo Pro 90 would be the more realistic option with zoning valves (Thermo 90ST is an old model by the way) Another advantage of the 90 Pro is reduced service component cost and higher reliability than the TTC. If you intend to use matrix instead of radiators then take great care in their selection and even the decision to use them, they are noisier and less efficient than rads. If correctly installed and serviced then redundancy is less important than you may think. Your cost comment is misinformed, a pair of marine spec TTCs would be far more expensive than a Pro 90. You may also want to consider a DBW2010 or a pressure jet boiler if you will be living aboard, much greater reliability as evaporator heaters of any make and size are not the best choice for heavy use operation.

 

[Paragon]

Hi David

Many thanks for your reply, the cost misconception was interesting, watch out for a PM. Are there reasonably sized passive radiators that can reasonably be fitted to today's modern yacht? Household rads don't seem to be an option, other than perhaps some towel radiators which I guess is why a lot of people go down the matrix heat exchanger route.


Thanks again.

John

 

[LadyInBed]

I know nothing of boat rad systems, I don't know if they work off engine hw, gas or electric, but as a backup system I would also install mains 500w fan heaters. Cheap and easy installation, instant dry heat and easy to reach out of bed and turn one on in a marina

 

[Paragon]

I guess we all have a fan heater in a locker on standby "just in case" but when you're living aboard full time you're looking for a more permanent "home style" heating solution that can be programmed to come on at certain times of the day and be controllable. Inevitably this is a substantial investment and, much like the heating at home, you want reliability and efficiency without the need to rely on oil filled rads or fan heaters except in an emergency.

David's comments were illuminating and have made me rethink the 1/2 idea but the distribution of heat in a water based system still provides an issue. I understand that heater matrix blowers work but are not that efficient and getting marine suitable radiators seems to be a challenge.

The search continues!