Radiant Heat question

[nyrussell]

Ok, need a new mainfold system for the heater before it goes back in. The installer made it impossible to isolate the loops and then I also need to install a few more loops to isolate each area (or i can simplify and do one 3 loops plus the overflow loop.

First idea - each area has its own loop: Aft Cabin; Saloon; Forward; Overflow; generator (heat exchanger); 2 cat (heat exchangers); then a loop for fill and last one up to the aft deck/flybridge. pexsupply.com recommends this on: http://www.pexsupply.com/Mr-PEX-408-05PK-8-Loop-Stainless-Steel-Manifold-Package-1-2-8377000-p . Personally the http://www.pexsupply.com/HydroPEX-H...utlets-and-3-4-PEX-Inlets-8-outlets-4952000-p works better I think for my application. Each loop would be isolated by ball valves to allow work to be performed without introducing air or draining any more than necessary.

Second idea - 4 loops: fan units inside the yacht (aft, saloon, forward), engines and genny. aft deck/flybridge, and overflow.

Third idea - one large loop with ball valves installed to allow isolation (I will be doing some of this anyways to allow removal of fan units anyways).

Ok, best method versus easiest, etc...

Thanks

 

[SKYCHENEY]

One large loop is the easiest to install, but you will have valves all over the place. The cleanest, prettiest, and easiest to get to is that large manifold with separate loops. But, that will be the most work to install and use the most hose. Your choice: More work up front and easier maintenance, or less work now, less cost, and more hassle to maintain later.

 

[REBrueckner]

Noel,
If you have to remove a single fan heater, say because it develops a leak, for replacement you can seal it off by using a vice grip and a pair of small pieces of anything flat to clamp the hose closed on each side of the heater, while you replace the heater ..I used small squares of plywood....you could also insert a temporary hose section (to replace the heater) with proper size nipples if you need heat...

Or compromise and use a few loops...for example I fed a 3/4 hose across to the opposite side of my engine room from my diesel heater, then split into one 5/8" hose forward and one aft (two loops)....I happened to have three remote heaters forward and three aft....in other words three heaters per loop...
as long as the total length of hose loops is about equal, so is the resistance and the water splits equally....I opted against individual loops: too many valves, too much hose, and takes up too much room....

I would suggest shut off valves either side of your diesel heater to make removal and repair easy.....I added those after several years when I had to remove my diesel heater anyway...

 

[nyrussell]

Rob,

There will be ball valves at every point needed for removal. I wonder how much hose I would save by pulling the half as**d manifold setup I have now (only one side has ball valves, return has no kill. Big question, which manifold set? I am partial to the copper but.... And I'll give ya a call Rob after this week to help hammer out the little stuff.

Thanks

Noel

 

[sandspur1966]

I got some bronze ones with my unit I purchase from Sure Marine in Seattle. They are knowldgeable and have everything but im sure you could source most of what they sell locally and cheaper.

I decided to go with a manifold instead of a continuous loop not so much for maintenance reasons (If you need to remove a blower unit you would probably clamp it off right at the unit anyway instead of draining a whole loop.) but for heat direction. I have one loop heating forward 2 cabins, another the aft 2 and a third heating the main salon and wheelhouse.

I was told that I may want to be able to limit flow to one loop as a way to direct more thermal mass/heat to a different loop, particularly during frigid periods.

In reality I simply dont do that. My boiler is 120k BTU and even in sub zero weather has never reached a point where it was running flat out.

Short version is... If I had to do it over again i would have gone with a simple single run.

 

[REBrueckner]

As sansdspur notes aove, many loops are hardly a necessity.....but adding a loop could be useful if the last few heaters in a single big loop system are cool enough not to provide enough heat....
depending how how fast coolant circulates, the first heaters in a big loop (closest to the diesel heater output) will usually be hotter than the last few heaters.....that was the major reason I opted for two loops in my six heater system....
For those who want a single big loop system, you can also opt for slightly larger heaters at the end of the loop...these will extract additional heat from the coolant....

Another variation is to utilize and single heater with double or triple air outlets..and duct air the last six or eight or ten feet to a compartment/cabin/stateroom. I happened to use one such unit in my system and liked it the best because the fan heater sound was in the engine room, not a stateroom....

And for those installing for the first time, if you guess wrong during the first installation, you can oftwen switch/exchange a couple of heaters after the initial installation to balance things a bit differently....or locate fan sound further away....During my first winter season of heater operation I added a heater in my engine room and ducted air above to my salon.....on non sunny days the salon did not get as warm as I liked....

And don't forget passive baseboard heaters (no fans)...I used them on the perimeter of my engine room...just tubing and fins, no covers, to minimize space taken....

 

[SKYCHENEY]

I've only done this once on a 40' motorcoach. I used a single loop to heat domestic hot water, engine preheat, and 4 or 5 fan heaters. It worked great, but as Rob noted, in a large loop, you may have problems heating the last few heaters in the loop. It all depends on how much hose you want to run.

 

[nyrussell]

The hose is run, however I am looking at rerunning with pex (as I have it left over and need to isolate the loops already there, big question is do I add a few loops to make it run better and if so... which ones

Noel

 

[SKYCHENEY]

It you add loops, you will want ball valves on the so you can regulate how much water travels thru each loop. They will probably have different lengths and that alone can cause some to get less flow unless you can regulate them.

 

[nyrussell]

need them anyways to isolate the lines... the question is which is better, copper or stainless manifolds (Big $$$$ difference)

Noel

 

[SKYCHENEY]

For the price, I'd go with the copper and add my own ball valves.

 

[krush]

Run 1 big loop and then just tap into it parallel (like wiring) for each coil.

 

[nyrussell]

Krush,

Most of the lines are run already....

 

[sandspur1966]

The one I got from Sure Marine was cast Silicon Bronze and had the space for 4 loops.

I used three loops for different zones and one for a coolant treatment filter which, if you have no copper or bronze fittings, you may not need as badly.