DHW Coil

I'm putting in a DHW coil and taking out my electric water heater. I don't want to keep the tank for storage. Do I need to put a pressure relief valve somewhere around the coil? The water heater has one but it holds 50 gallon of hot water. Not sure if I need a PRV for the coil. I'm putting in a tempering valve and a flow restrictor. Is there anythng else that I need?

Bill, I would suggest going the extra $ for the better tempering valve. this Watts one ($45) has twice caused havoc due to mineral build up. No real need for prv in dhw coil only circut but if I had a spare one around when doing the job I would prolly put it in. just the overdoer in me I guess.

Bill, many times we will install a small expansion tank in line, and as Eagle says, upgrade one level above that Watts valve shown. You can take it apart and clean it, but it isn't much fun unless you install a handful of valves. Try to give yourself enough room for tools. You should be done by now, what's the hold up?

whistlenut wrote:Bill, many times we will install a small expansion tank in line, and as Eagle says, upgrade one level above that Watts valve shown. You can take it apart and clean it, but it isn't much fun unless you install a handful of valves. Try to give yourself enough room for tools.You should be done by now, what's the hold up?

No coil yet. Should be coming into the dealer this week. I'll pick it up next Saturday if the dealer receives it. I bought an Amtrol valve from the local supply house. I have the room so I may just put in a small expansion tank. I'd rather be safe than scalded.

Oops, was rushing you......Good choice on the Amtrol. Good stuff. Remember to thank Steve when you effortlessly spin off those nuts, remove the plate and are able to install the coil. EFM has made the process much easier now, but for the thousands who don't have the new setup, we want to save as much time and skin as we can.

p.s. isolation ball valves in front and back make servicing quicker. I hate when I forget them and have to drain the house....again...

Just to save 10 bucks in valves, too.....................

A pressure relief valve on a coil is mandatory in my state (Maine). It seems in PA you can do what you want.

Plumb out from the coil and drop down 6" or so to the mixing valve. Put the PRV on the hot right next to it. Add valves and boiler drains to acid clean the coil when it needs it. Add the valves & drains now, or the first time it needs the scale cleaned you'll have to shut the whole system down & drain it to add the valves.

Freddy.
PA doesn't have a statewide standard that I'm aware of. It's up to the individual local gov't to set their own standards. I'm not sure if they follow state guidelines or the National building code. When I bought this place it was a deserted shack. I went to the township to pull permits. I gave the zoning officer a set of plans for the addition and a list of work I wanted to do. All new plumbing, wiring, some structural changes etc.The only permit I needed was zoning for the addition. He told me my house was my castle, and my responsibility. That's fine if you have a clue what you are doing but I've seen some butchered up stuff in this house. The bathtub was balanced on one floor joist. The only thing keeping it from rocking was the fiberglass surround. The rest were completely cut out so this moron could get his plumbing in. Rebuilding the floor wasn't something I anticipated but it got done.

Do you have to remove the coil from the boiler to clean it out? I've never done it before. I was thinking of putting two unions in the piping so it could come out quick to clean. If it doesn't need to be removed I can set it up with drains instead. Thanks.

No, you can clean it in place. Not a bad job with shut offs in place and unions too. You can power flush if the valving suits the pump you are using to clean the coil.

billw wrote:Freddy.
PA doesn't have a statewide standard that I'm aware of. It's up to the individual local gov't to set their own standards. I'm not sure if they follow state guidelines or the National building code.

PA adopted a statewide building code in 2004. If there is no local code adopted by your local government then the state code applies. See:

http://www.dli.state.pa.us/landi/cwp/view.asp?a=3 ... avrad3DFC3

In general the state code is the same as the 2006 International Codes.

Freddy wrote:A pressure relief valve on a coil is mandatory in my state (Maine). It seems in PA you can do what you want.

Plumb out from the coil and drop down 6" or so to the mixing valve. Put the PRV on the hot right next to it. Add valves and boiler drains to acid clean the coil when it needs it. Add the valves & drains now, or the first time it needs the scale cleaned you'll have to shut the whole system down & drain it to add the valves.

Freddy's 100% Yanche is also.

well we used to do what we wanted......... then most of us got ....married

billw wrote:I'm putting in a DHW coil and taking out my electric water heater. I don't want to keep the tank for storage. Do I need to put a pressure relief valve somewhere around the coil? The water heater has one but it holds 50 gallon of hot water. Not sure if I need a PRV for the coil. I'm putting in a tempering valve and a flow restrictor. Is there anythng else that I need?

1 temperature valve

1 back flow preventer

2 ball valve one cold side one on hot side

1 drain valve

1 flush valve incase you want to flush the coil out sometime down the road

Freddy wrote:A pressure relief valve on a coil is mandatory in my state (Maine). It seems in PA you can do what you want.

Plumb out from the coil and drop down 6" or so to the mixing valve. Put the PRV on the hot right next to it. Add valves and boiler drains to acid clean the coil when it needs it. Add the valves & drains now, or the first time it needs the scale cleaned you'll have to shut the whole system down & drain it to add the valves.

Freddy -- would you please post a picture of how your set up for cleaning the coil - the valves and such that you hook to? Or point me to a picture you have on site? And would you also post picture of the cleaning set-up? I am more of a graphical interface gut - a picture is worth a thousand words to me, and I think I might finally need to clean that coil this year
Please remind me the chemicals that you use and the circulation time. When to stop- you know those little points that make the job a success!

Thanks in advance
Sting

I don't have a photo as I don't use a coil for hot water so I made this sketch. I found a write up on line about cleaning a coil. A couple things....The acid should go in reverse direction of water flow. Run until it flows free, but not over 5 min. IF you blow a coil by cleaning it, it was dead before you started you just hadn't seen the obituary. Make sure to cover the acid bucket, splashing is bad. Wear proper skin & eye protection. The fumes.... I don't have to say not to breath them because you can't. Half a breath and it locks you right up....followed by coughing to clear.

1. First, confirm the diagnosis that the problem is clogged piping, not a clogged strainer, valve, or improper pipe connections (such as use of too much solder on copper piping connections). Some types of pipe or tankless coil clogging such as due to sediment, rust, or mechanical damage will not be corrected by an acid flush.
2. Install shutoff valves and drain valves at each end of the water supply piping (or right at the tankless coil inlet and outlet piping)
3. Shut off water supply to and then drain the piping or tankless coil to be cleaned
4. Connect the two drain fittings (at the two ends of the copper piping or tankless coil) to hoses (often washing machine hoses are used) as follows:
1. One drain hose empties into a bucket
2. The other drain hose is connected to a "pony pump" capable of pumping acids
5. Prepare the acid flush mix: The bucket receives a few gallons of a cleaning acid selected by the plumber (such as muriatic or dilute sulfuric acid)
CAUTION: Acids can cause dangerous burns or loss of vision: appropriate hand, eye, and skin protection are needed as well as protection against acid spills.
6. The acid is pumped cycling through the piping or tankless coil to be cleaned.
7. The acid is flushed from the piping or tankless coil using fresh water
8. The hoses and acid are removed and the drain valves closed.
9. The plumbing water supply to the cleaned section of piping or tankless coil is turned back on
10. The plumbing system is flushed to be sure no acid remains in the piping