Things that make you say, \"Hmmmm?\".

Paul Rohrs_2

I completed a radiant floor heat design and quote at my contractors request the other day. It was a very small job and didn't take much time. My contractor took my quote and from across the counter began to "Itemize" saying that the system was so small, he didn't need an air-separator, or PRV, and since he was going to use a water heater as a heat source,(hate it when that happens) he didn't need an expansion tank.
The truly disheartening part wasn't not getting the job,(frankly I was relieved), it was that this was a liscenced mechanical contractor!
I am thankful to read and hear of qualified professionals who bring credit to our industry.


Paul

Gary Fereday

Hummmmmmmm~~~~~~~

Sheesh! I bet your happy that you did not get into that. Some times it is best to let sleeping dogs lie. I cannot imagine a contractor of any kind letting himself into a mess like that. Just the water expansion thing alone is something that needs to be addressed. Hummmmmmmm is an understatement!

hr

Actually

I rarely use prv or fill valves. I prefer a manual fill and a low water cutoff for best protection. Prvs have a habit of not working after years of in-activity, and can also stick and over fill and pop relief valves when they are called on. Most fill valve manufactures suggest you turn them off after initial fill and purge. Why bother installing them?

I have seen plenty of systems with just small air vents for the initial fill and purge work fine for years. Plenty of old baseboard systems with just coin vents on the board and a small bucket vent on the boiler. Air purgers are cheap 10 bucks for a good old iron air scoop. Why not for that money. I'm not convinces spiro type air scrubbers are always needed in a small simple easy to purge system.

I've also done a bunch of 6 gallon electric tanks connected to a couple small loops of radiant without expansion tanks. Fill them to 12 psi with 60 degree water and they run up to about 25 psi at 130 degree.

If the water heater has an approved 150 psi 210 degree T&P (most are shipped with them installed these days)and the pump and other components are listed for that pressure you are safe and well within the operating range at 25 psi. I add a second 30 lb relief for a piece of mind and have never poped one open yet. The amount of pressure increase is related to the system capacity and the delta T.

Once again a #15 extrol isn't that much money. If someone is shopping you for the cost of a #15 and iron air purger, you'll probably never be cheap enough to get that job

hot rod

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Paul Rohrs_2

Hot Rod\ System filling

> I completed a radiant floor heat design and quote

> at my contractors request the other day. It was

> a very small job and didn't take much time. My

> contractor took my quote and from across the

> counter began to "Itemize" saying that the system

> was so small, he didn't need an air-separator, or

> PRV, and since he was going to use a water heater

> as a heat source,(hate it when that happens) he

> didn't need an expansion tank. The truly

> disheartening part wasn't not getting the

> job,(frankly I was relieved), it was that this

> was a liscenced mechanical contractor! I am

> thankful to read and hear of qualified

> professionals who bring credit to our

> industry.

>

> Paul



Dare I open the can of worms about codes. Yes they vary across the country, but are Double-Check backflows code in your area? RPZ's on systems with Glycol?. I know 50 miles from here in Omaha, they use no PRV and isolate with a ballvalve. Your filling of systems seems tried and true, I assume you also recharge your expansion tank from it 12 PSI setting as well?


Paul

Paul Rohrs_2

Codes

Dare I open the can of worms about codes. Yes they vary across the country, but are Double-Check backflows code in your area? RPZ's on systems with Glycol?. I know 50 miles from here in Omaha, they use no PRV and isolate with a ballvalve. Your filling of systems seems tried and true, I assume you also recharge your expansion tank from it 12 PSI setting as well?


Paul