Expansion tank max rating.

icy78

I see 100 psi max pressure for an Amtrol 90 tank. Is that max allowable bladder pressure or is that burst pressure?

bob eck

What are you using this tank on most boiler systems run 12-18 psi with a 30 PSI relief valve. Some boilers might go up to 50 PSI max.

hot_rod

I would say that is the max operating pressure that the manufacturer listed the tank to.

icy78

This tank and fill are set at 24 psi although it's too much, but that's what the owners want. I just noticed it said 100 psi max. The relief is 125psi. My thought was....which is the relief valve here? It scares me, for obvious reasons.

hot_rod

It is probably a water heater relief valve at that pressure rating?

When water heaters are used as hydronic heat sources you should add a 30 psi pressure relief valve, sized to the BTU rating of the heater. But leave the T&P in the tank for temperature and pressure protection, and liability reasons.

EBEBRATT-Ed

If it's a heating system you have to use an ASME (expensive) expansion tank if the relief valve on the system is rated more than 30psi

It's enforced if you have an inspector that know what he is doing.

In MA. the state boiler inspectors look at everything over 200,000 (unless installed in a house) & enforce this

icy78

It's a Raypak boiler heating system. H3-0724. 726kbtu I think.

Gordy

I would hardly think any rating is to the point of failure.

Leonard

Don't know about expansion tanks, but believe in general pressure vessels ( tanks) are stamped with rated max operating pressure, burst pressure is higher, maybe 2-3 times higher. I've hydro tested some prototype 6,000 psi cylinders out to ~ 11,000 psi for safety before I filled them with a gas to 6,000 psi, then held them in my hand.

Think the tank ASME rating requirement comes from fact that compressed air can store lot of energy that can become very destructive if tank bursts. Think shrapnel. They likely assume worst case of 100% air or steam in tank. Guess they made the judgement call that its doesn't contain enough energy to be too destructive < 30 psi. Maybe at 30 the energy is mostly dissipated in tearing the steel wall

icy78

> @EBEBRATT-Ed said:
> If it's a heating system you have to use an ASME (expensive) expansion tank if the relief valve on the system is rated more than 30psi
>
> It's enforced if you have an inspector that know what he is doing.
>
> In MA. the state boiler inspectors look at everything over 200,000 (unless installed in a house) & enforce this

Hmmmm. So 125psi may not be the correct relief for this boiler. I'd better check.

Gordy

Ahh no.

Jamie Hall

125 psi is definitely not right -- no system should have the pressure relief valve set greater than the rating of a component! And for a heating system, it should be at 30 psi. However, you do need the temperature relief as well -- so I'd leave the 125 there, and add a 30.

icy78

> @Jamie Hall said:
> 125 psi is definitely not right -- no system should have the pressure relief valve set greater than the rating of a component! And for a heating system, it should be at 30 psi. However, you do need the temperature relief as well -- so I'd leave the 125 there, and add a 30.

DANG REALLY!? Your saying no way the boiler came withthst valve? (You guys would gag if you saw this setup). So I'm right in thinking that the ex tank may be the "relief" (by blowing up) before the relief valve?

hot_rod

It sounds like you have a copper tube water heater, not a boiler? Then it would have a high pressure relief. The Raypak Hi Delta could be a boiler or DHW heater.

I have seen copper tube DHW heaters and also pool heaters used in hydronics. Sad.

I doubt the expansion tank would burst before the 125 relief triggered, as noted above the tank may be tested to twice or more than rated
Probably would not see burst pressures listed on a tank like that.

Leonard

Would guess ASTM rated tanks are all pressure tested, not just test several samples of the production lot. But not familiar with typical tank testing , my 6,000 psi one was a prototype for special application

icy78

> @hot rod said:
> It sounds like you have a copper tube water heater, not a boiler? Then it would have a high pressure relief. The Raypak Hi Delta could be a boiler or DHW heater.
>
> I have seen copper tube DHW heaters and also pool heaters used in hydronics. Sad.
>
> I doubt the expansion tank would burst before the 125 relief triggered, as noted above the tank may be tested to twice or more than rated
> Probably would not see burst pressures listed on a tank like that.

Youre right Hotrod, I found out this morning it is a waterheater. The ex tank is 100 psi and they are going to change the relief to something below that with same capacity rating. I am thinking liability IF it popped which is why I questioned it?
Why is it sad to use that heater as a boiler?

Leonard

120 psi relief is odd, 120 psi will push water up 268 feet ( ~ 26 stories) . Don't think your building is that high.

And at 120 psi water won't boil till 350 degs F, makes for a lot of dangerous steam if it releases. Will flash to steam.

EBEBRATT-Ed

They don't list "burst pressures" on tanks, they list maximum operating pressures. MOP means that's what it is rated for..working pressure.

We have installed many commercial boilers into systems that have existing "regular" non ASME expansion tanks. Sometimes these boilers come with 40, 50 psi relief valves. To get around having to replace a perfectly good operating non ASME expansion tank with a new expensive ASME tank we just put a 30psi releif valve on the boiler. (as long a building height and system required pressure allow this)

Don't know about other locations but in MA. this is enforced

icy78

> @EBEBRATT-Ed said:
> They don't list "burst pressures" on tanks, they list maximum operating pressures. MOP means that's what it is rated for..working pressure.
>
> We have installed many commercial boilers into systems that have existing "regular" non ASME expansion tanks. Sometimes these boilers come with 40, 50 psi relief valves. To get around having to replace a perfectly good operating non ASME expansion tank with a new expensive ASME tank we just put a 30psi releif valve on the boiler. (as long a building height and system required pressure allow this)
>
> Don't know about other locations but in MA. this is enforced

I tried to get them to put a 30 on . I'm sure the system pressure could be 15 not 28 as it is now. I have no idea why this boiler was put in either.

I am a refer tech for this company, the boiler is in their building. First time I've worked on it. I have to tread carefully because the owners installed it! Can you see now why I'm studying heating systems? ☺

EBEBRATT-Ed

In this business things are done wrong on a daily basis. You would think after a while everyone would get smart...not happening!!!

Good thing your paying attention and thinking about the way things should be.. Most don't care

hot_rod

icy78 said:

> @hot rod said:

> It sounds like you have a copper tube water heater, not a boiler? Then it would have a high pressure relief. The Raypak Hi Delta could be a boiler or DHW heater.

>

> I have seen copper tube DHW heaters and also pool heaters used in hydronics. Sad.

>

> I doubt the expansion tank would burst before the 125 relief triggered, as noted above the tank may be tested to twice or more than rated

> Probably would not see burst pressures listed on a tank like that.



Youre right Hotrod, I found out this morning it is a waterheater. The ex tank is 100 psi and they are going to change the relief to something below that with same capacity rating. I am thinking liability IF it popped which is why I questioned it?

Why is it sad to use that heater as a boiler?

That unit is built as a hydronic boiler H, DHW version WH and a pool heater version HLW. Different listing standards apply. The DHW version doesn't have the required H stamp according to their documentation.

I don't know all the legalities, the fact they offer it as 3 different models, must be some code issues?

The DHW version is available with a choice of relief valves, probably has bronze or closed headers instead of cast iron.

A Raypak rep may be the best source of clarification.

I know one company that tried sneaking copper tube pool heaters into several radiant jobs, less $$. Inspectors shut him down.

icy78

The other thread I started about HI 02?. Same boiler.

icy78

> @icy78 said:
> The other thread I started about HI 02?. Same boiler.

Whoops. It was 02 rising to 10-11.

Leonard

The 120 psi relief valve has got me wondering, what would be legitimate uses of such a high pressure valve? ~ 700 k BTU/hr is higher than a regular house but not a skyscraper.

icy78

> @Leonard said:
> The 120 psi relief valve has got me wondering, what would be legitimate uses of such a high pressure valve? ~ 700 k BTU/hr is higher than a regular house but not a skyscraper.

@hotrod pointed out the boiler is designed for a domestic water heater application. Hence the 125 rating.

hot_rod

Pretty much all water heaters, DHW storage tanks, or DHW boilers have 125 or 150 psi relief. T&p Valves found on tanks have a 210 temperature component also

I suspect the unit is in violation of your codes without an ASME H stamp. An inspector should have tagged it. Some serious liability for the installer of that, I suppose?

icy78

> @hot rod said:
> Pretty much all water heaters, DHW storage tanks, or DHW boilers have 125 or 150 psi relief. T&p Valves found on tanks have a 210 temperature component also
>
> I suspect the unit is in violation of your codes without an ASME H stamp. An inspector should have tagged it. Some serious liability for the installer of that, I suppose?

You guys are all missing that the company I work for installed it and it heats their offices!☺ I don't know how to find the code (s), I doubt there was any inspector involved. I would like in a delicate way for them to understand that some of their employees are getting smarter and will catch them on this stuff now.☺ if I could find the code and prove it it would really help. If someone could help me out with that I could pm my state. I like the company and they treat me well but we need to do things right.

hot_rod

I think the term is whistle blower

Leonard

Ah ..... think I see now . on DHW only boiler your running at city water pressure that could be high. We've got 95 psi city water down near river level of town, 42 psi up on a hill.

icy78

> @Leonard said:
> Ah ..... think I see now . on DHW only boiler your running at city water pressure that could be high. We've got 95 psi city water down near river level of town, 42 psi up on a hill.

No. Well pressure is 60psi max. It is a WH used as a boiler. As @hotrod said. Wrong application.

icy78

> @hot rod said:
> I think the term is whistle blower

Ouch. But not true, although not knowing the whole picture I can see why you said that. I guess in a way, it would be internal whistle blowing? So that would be me in trouble LOL. Don't I have a responsibility as an employee to point out where as a company we can do better?
When I screw up on a service call I sure want to know about it, otherwise I won't improve on that type call.

No hard feelings on my part. Last night I was pretty ticked but further reflection showed me it would be logical to arrive at your conclusion.

Cheers! And I appreciate all the knowledge and help you all have given.

hot_rod

If you want to keep going with this, gather facts. Is the equipment in violation of local or state codes. A call to the AHJ or State boiler inspector would clear that up.

Then present that to the person that installed and or purchased the equipment. It could be an honest ovrsight that the correct product was specked or ordered, but the wrong one was delivered and installed

Assuming again that it IS in violation.

It seems this is eating on you. Follow through or ignore and move on.

icy78

Thanks hotrod. I really want our design guys to understand what I'm seeing, but I can't get the point across without appearing to put someone down. So I'm just going to write my service report and leave it. I don't want to point out violations im not even sure of and make friction at work. It's all in house. I just want it safe for the office folks directly above the boiler. So I told them the questions i have with it and could they please look it up and tell me what they want done. Everybody is friends still and we're heating and have a 50 psi relief now so at least thats better. Thanks again for your interest and input.