Thermal Expansion Via Iraq - Contractor Talk - Professional Construction and Remodeling Forum

jicoll2000 · 12-13-2006, 01:39 PM

Just got here in Iraq at a base in the Sunni tri-anlge. I am taking care of all the hooches in the camp of the contractor I work for. They all have 50 litre (Mostly) hot water heators and are failing at a rate of about 2 to 3 a day. Seams are splitting, no explosions as of yet. They are all 220 heaters. The safety valve if you want to call it that is made in Jordan, hooks to the cold water side of the tank and is also equiped with a check valve right after the pressure relief spring. This is a dangerous situation. I am correct I believe, Im plumbing here with a bunch of Bosnians that insist that it is safe, I know better. Not only does this check valve prevent the control of thermal expansion, does this not create a closed system, and thermal expansion excist only in the tank it self. Also they are constantly replacing these so called saftey pressure releif valves due to the fact that they leak. This is a direct result of the check valve on the relief valve, with no expansion control tank in between the check valve and the heater. I have argued this point over and over again. I have been refusing to install these relief valves without first removing the check valve, this is easy done with a hammer. Thus creating a open system. Help! How do I explain to these guys that what they are doing is potentially a ticking time bomb. There are over 800 of these little hot water tanks that I am looking after. We have resently requesitioned some Rheem 20 gallon tanks with t and p valves on them and are floor models. Ill be damned if they are not attempting to place check valves on them with out thermal expansion tanks. There argument is that the hot water is going to back out of the tank due to a broken pipe or something and the element is going to come on. This is true in the tanks that we are replacing that reside on the wall above all the fixtures but so what, I would rather a element come on a empty tank than one filled with water. The floor modes are not going to empty any way there below all the fixtures. Gjive me some advice on this.

Ron The Plumber · 12-13-2006, 07:30 PM

Quote:

The safety valve if you want to call it that is made in Jordan, hooks to the cold water side of the tank and is also equiped with a check valve right after the pressure relief spring. This is a dangerous situation.

Like this? Please explain how it connects.

jicoll2000 · 12-13-2006, 08:49 PM

Yes,
but the inlet and the outlet lines are on the bottom of the tank and the check valve is on the safety valve , it looks like a for want of better term, a street coupling.

jicoll2000 · 12-13-2006, 08:50 PM

Yes,
but the inlet and the outlet lines are on the bottom of the tank and the check valve is on the safety valve , it looks like a for want of better term, a street coupling.

JamesNLA · 12-13-2006, 10:10 PM

you need to explain to them about expansion and why it's important. If they insist on the check valve, you need to have an expansion tank in between the check and cold inlet, just like a recirc.

Explain it to them like this, metal expands when warm, and contracts when cold so the pipes actually change size (a very small amount) the tank is made of metal, and if the water has no place to go, it will make a place to go. There has to be some good reason they want the check there, are they afraid of the water getting contaminated if there is a heater breakdown? I'm suprised supply lines haven't burst yet... Better you than me pal

Ron The Plumber · 12-13-2006, 11:17 PM

I'm trying to see what your seeing there, I never seen a tank where both in and outs on a tank were on the bottom.

So I'm trying to learn more about what your seeing there, I can not picture it yet.

Does it look like below and where does the outlet side of the T&P Valve go to?

JamesNLA · 12-14-2006, 12:39 AM

based off what I read, the check is in between the service supply and the "saftey" valve. If so, there would be no expansion back to the water tower, or however it's set up.

Ron The Plumber · 12-14-2006, 12:46 AM

I'm at a loss here, this safety device, are we talking about a T&P valve?

JamesNLA · 12-14-2006, 01:20 AM

"....check valve right after the pressure relief spring."

It sounds like at lease a Pressure

Ron The Plumber · 12-14-2006, 08:06 AM

If this is a PRV Valve (pressure reducing valve) then a check valve serves no purpose, for the PRV valve creates a closed system, expansion tank is needed if and only if the pressure created from heating exceeds 150 psi.

**Double-A** · 12-14-2006, 10:04 AM

Pressure in a closed system can rise from 0 (zero) psig to over 250 when heating 50 degree water just 10 degrees if there is no room for thermal expansion to take place.

I think regular T&P valves on the heaters will take care of over temperature and over pressure situations and a modified swing check valve on the inlet side, installed horizontally will control backflow.

A small hole drilled in the gate (the flapper thingy that actually swings) will allow for the thermal expansion to push back into the towers without allowing for a dangerous amount of backflow.

If you're using a closed and pressurized system, then a thermal expansion tank is definately in order. It should be sized to account for all tanks working at the same time.

If you can post a picture, and describe the supply and storage side of this system, we might be able to make further recommendations.

jicoll2000 · 12-15-2006, 08:37 PM

Yes,
the check valve is incorportated withing the pressure valve it self, it is just a pressure relief valve, no tempature relief on this. The check valve is after the pressure relief mechanism. What the main problem is and this is occurring the pressure relief valves that are either made in Jordan or Egypt are not functioning. Tank pressures are resulting in tank failures due to expansion, I believe. We get calls that the occupant is cleaning up the floor constantly from the pv valve leaking, Im not surprised, this is on the few occasions that the pv is actually trying to relieve the pressure that is residing in the tank. I have been physically removing the check valve that is incorportated into the pv valve with a small chisel.LOL!! Which resulted in the Bosnian getting very upset to the point of physical contact. I try to make it simple for him but to no avail, I just plainly ask him best I can, because he speaks very little english"Mirsad, why are all these tanks failing, 2 to 3 a day, in a population of around 700 tanks." He has no answer, or tells me I talk to much. It is a dishearting situation. I have no solution but to modify the pv valves until something better comes in the shop. This place is really f***-up. We do not, or will not buy any quality goods and everyone is in a potential dangerous situation, not to mention Im in Iraq.

Ron The Plumber · 12-16-2006, 04:05 PM

I'm still having a hard time picturing this setup, a picture would really help me, help you.