setting up radiant floor heating with HOT WATER HEATER

and some that are totally clueless. sort it all out and pick from the best,.
I heated my 3200 square foot house for 2.5 winters with a Bock oil fired water heater., I have 3500 feet of tubing in my slab. Oxygen barrier pex is a MUST. I use a heat exchanger. I do not want legionaires disease. I have 15 zones and two pumps. You use zone valves not 15 pumps.
I currently am heating my home with six solar hot water panels, and a home made wood fired boiler.
for photos of the layout of my house go to.
http://www.pbase.com/ericjeeper/pole_barn_house
and to my solar set up.
http://www.pbase.com/ericjeeper/solar
Good luck. a good web site to ask for assistance is Heatinghelp.com. go to the wall

ericjeeper,

Your system, and building, look great.

Thanks,

Alex

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Thou art That

This is GREAT everybody! THANKS SO MUCH! We are still trying to learn before embarking upon this great task.

CarolK - We were given a 40-gallon HWH I think but plan to give it to someone else and get the one we really need, IF that's what we go with. Seems I will need to do some calculating on the # of total feet (we did keep the loops under a set # of feet but I can't remember if it was 250 or not) and the diameter of the pipes plus the water in the manifolds, tank, etc. to see how many MINIMUM gallons of tank capacity we would need.

OK, so if the expansion tank is above everything else in the crawl EXCEPT the loops on the floors above, will it still work or will I get airlocks?

frazzlehead - thanks, I will PM you!

ericjeeper The Bock is the boiler we WANTED but oh man was it spendy just to get it here (no one carries them in-stock and it will take months to get one ordered. I almost bought one off eBay last year for $2500 new but the BTUs were too high for my needs I think... or something. lol). Anyway, we really want to ferret out this HWH vs. boiler issue to see if it is really do-able.

Has anyone used a HWH for this use and NOT had it work properly? Apologies if you have and have said so here, it has been a week or so since I was last here reading so need to re-read the posts to date...

ericjeeper and others that have mentioned this - I believe we did use oxygen barrier PEX but how do I check? It's red and made for high heat. It does have printing on it but I would have to go to the crawlspace to look at the exposed tubes under the first floor (not yet running so joists not yet insulated in some areas).

ericjeeper - can you expand on your Legionaire's Disease comment? I know the causative bacteria are thought to grow in stagnant water but how would a heat exchanger help you if that happened?

I am NOT mixing domestic potable water with the heating system. I am keeping them entirely separate (except that if we use an open system, they may get the same supply but I'd rather do a closed system filled with distilled H2O).

Respectfully, I have a question.

A tank holds 'X', and manifolds hold 'Y', and all my PEX holds 'Z'.

Who cares? it will never fit into the tank anyway. Whether my tank holds ten times the amount in the rest of the system, or if my tank holds an equal amount as the rest of the system.

It is a dynamic system, the water is always circulating.

I am never going to drain the PEX tubing and try to get it to fit inside the tank.

So why?

If I need 80,000btu, then I need 80,000btu. Regardless of the size of the tank.

What am I missing?

My apartments each have a commercial furnace [$$$].

Our house has a HWH. I got it used from a appliance repairman. He was expanding onto his house, doubling his btu needs and this HWH would no longer be enough btu. It had heated his house, now it heats mine. Granted I do not have all insulation in place yet, so I still need the woodstove at night to supplement. I anticipate that once the insulation is completed this HWH should be enough btu.

ET1 SS - well that's why I initially thought I could use a smaller tank and I think that's what I read once or twice before too... Not sure... lol

I was totally shocked when we went to Sears Roebuck and looked through their HWHs. Different sizes, ratings, etc. I wanted to know their BTU output, and we were shown a thick binder. Every propane HWH that they had and every propane HWH that they could order for us, all had the same btu capacity. Looking more, they all use the same burner inside. Just different sized tanks and thicknesses of insulation. The burner where propane is burned is the same, and the hot pipe inside the donut is the same [where the water contacts heat, from which it gets hot]. I walked away with an entirely different view of HWHs.

And at $150 [approx] a piece, even if they burn out between 5 years and 10 years later, it is still cheaper than a water-boiler-furnace.

ET1 SS - it's even better when you can get one FREE. Usually you have to replace the anode but the used ones that people take out of their houses and replace are almost always on the recycling groups.

I am still looking for the REALLY good site I had a few years back. It must be buried on my other old computer. *sigh*

I did find this site that has some helpful diagrams though. Anything wrong with these pictures?

http://www.radiantcompany.com/system/closed.shtml

I would not be using glycol.

I noticed that in the very first diagram it does appear that they are using a separate pump for each zone... Thoughts?

I have replaced heater elements in HWHs.

I have also had to replace HWHs when they were full of sand. At the time, I did not have the time to deal with it. But I have seen many HWHs thrown out full of sand. If you can flush them out they would be fine.

Nice site.

I would not use glycol either.

You can use multiple pumps, or not.

I have multiple pumps, but mine are: one 120VAC and one 12VDC.

OK, I verified, we did use oxygen barrier PEX. Whew! I thought we had but I got worried when I didn't have the answer right up front for sure. They do sell both kids at the home centers so I was glad to see we hadn't messed up this part.

Still need to find that other site for you guys to pick apart. It had all sorts of information on why thermal mass with gypcrete doesn't really work the way we'd think and why hot water heaters are OK vs. boilers and lots of diagrams and such. *sigh* I hate being this disorganized!

OK, I verified, we did use oxygen barrier PEX. Whew! I thought we had but I got worried when I didn't have the answer right up front for sure. They do sell both kids at the home centers so I was glad to see we hadn't messed up this part.

Still need to find that other site for you guys to pick apart. It had all sorts of information on why thermal mass with gypcrete doesn't really work the way we'd think and why hot water heaters are OK vs. boilers and lots of diagrams and such. *sigh* I hate being this disorganized!

I have installed about 20 boilers, gas and 3 oil fired in the last 3 or 4 years. I have to say boilers are made for the job, they have all the gauges and safeties built in. You can get one for less than $1,500 that will do all you need. Most will come with a transformer built in(24 volt), to control your valves at each zone. I have always used a good master tstat and zone control tstat for the zones. Because I have always installed new as I am required to warranty anything I do for a year, that's all I could do. You can get online and shop for a used master and slaves. You can also get solenoid valves online, buying used you will save a lot and places like Ebay usually let you know if the part works. If you get on one of the hot water boiler company web sites you can pull generic stamatics up to see how they are run, fairly straight forward. Not easy but not rocket science. If I can help pm me and I'll try.

P.S In saying that I have our Churches baptistry hooked up to a 50 gallon hwh, It comes on at midnight and off at noon Sunday, it does alright, but if we had extra money I would change it to a boiler. We could have it come on at 8:00 am and save money on gas.

A 40kbtu HWH burns propane at one rate.

A 100kbtu boiler burns propane at a different rate.

If today the 40kbtu WHW burns from 24:00 and the church is toasty at 10:00 [10 am], then a 100kbtu boiler which burns almost three times the propane per hour; it would be a close call which would be cheaper to operate.

Since the big unit costs ten times as much to purchase, you would have to go through ten HWH's lifetimes to equal the life expectancy of the boiler.

I think you are better off using the HWH.

Or two HWHs if that fits your need better. Twice the btu and still not nearly the consumption of propane.

all I'm saying is that hwh are not meant to burn constantly. if you look at the cheap burners that come on them you will see what I mean. You do save money on the hwh. The burn rate of 40,000 vs 80,000, doesn't mean half the time. The recovery of an 80,000 is less than half. Also better burners, heavier tank, all the gauges it seems for the added money just the peace of mind is worth something.

I'm very frugal, I'm redoing a 12/60 trailer as a way of living the way I want and not go in debt. I just feel some things need to have the equipment that was made to do the job. You could adapt a old pick-up to pull a plow but a tractor just works better. With about 30 years HVAC I have seen fires started by undersized wires, people get sick from co and mold growing in duct work because people oversized their units. Brand is not important but right equipment is.