New Amtrol Boiler Mate running out of hot water

mplsheat · February 2012

We just had a new IBC SL20-115 boiler and Amtrol boilermate CH-41ZDW indirect professionally installed and we run out of hot water after ten minutes of running just the hot water. I have a faucet that puts out 3 gpm's and I got cold water after 10 minutes. I have it set to 125 - 130 degrees (thats measuring it with a meat thermometer). Domestic hot water is priority and we have a grundfos circulator supplying the heat. The thermostat on the amtrol turns on after 6 minutes and then at 10 minutes the water is cold.

Is this normal?

Also, when the IBC ignites, on occassion it will pop pop pop, then ignite. Like it does not light up very well.

What could these issues be?

Steve Whitbeck · February 2012

3GPM

Did you tell your plumber that you had a faucet that used 3 GPM???

You have a 41 gallon storage tank and you draw 30 gallons off of it and run out of hot water - that is probably normal.

The entire tank doesn't have 120* water in it - the bottom of the tank has cold water.

With that demand I would have put in at least a 60 gallon indirect.

Robert_25 · February 2012

Undersized

I agree with Steve, the indirect is undersized for that kind of load. I have a fast-fill fixture in our tub and it would quickly exhaust a 30 gallon indirect...I have an 80 now and have never gotten ahead of it.

BM12 · February 2012

Anti-scald Mixing Valve

Does anyone use mixing valves??

Why not Improve the results by Installing a Mixing Valve and turning the tank up to 140 degrees.

Mix 10-15% Cold with the Hot and get 10-15% more Mix.

Might not fix the problem, but it can't hurt

billtwocase · February 2012

gotta disagree

I have a 41 gallon Amtrol in my own house with a 5 GPM flow, and never run out of hot water, and the tank about 25 years old now. How is it zoned, piped, prioritized? 3 Gpm is child's play for that tank, if it is installed right, and has a sufficient boiler to heat it

Steve Whitbeck · February 2012

Bilt

Yes - But what size boiler do you have feeding it. If you had a 200,000 BTU boiler you would never run out of hot water. But with 115,000 it would be a problem. There is no way that a 115,000 BTU boiler is going to recover 30 gallons of hot water in ten minutes.

Jamie Hall · February 2012

Wait while I get the calculator...

30 gallons in 10 minues... assume a 70 degree temperature rise... about 94,000 BTU. if all the heat input to that boiler showed up in the hot water, it might, just barely, keep up. But that's kind of pushing it... I'll go with Bill.

Steve Whitbeck · February 2012

NO

Your assuming the boiler started when the water was turned on not when you only had 15 gallons left. Also the boiler has mass and 3 gallons of water itself that has to heat up first. Plus what mass and water that is in the piping between the boiler and the indirect. I say it runs out before the boiler can recover. Plus the initial post said cold but 80* feels cold from a faucet when compared to 120* water.

billtwocase · February 2012

It is possible

My boiler is a Utica SFH 3100 3 section cast, input is a .65 at 140 PSI, about 79,000 output, 3 Honeywell zones, 2 heat, 1 indirect, 2200 SQ ft raised ranch, 4 adults, max boiler operating temp is 180*F, and never a problem. The boiler maintains 100*f or less, don't like cold start. The thermostat on the tank is set to maintain 125*F, no mix valve. I've installed a lot of these tanks, and never had a complaint, other than the Smart control issues, and the coil design of the mid 90's? Soldered piping issue. His tank is probably not installed to manufactures specs.

bill nye_3 · February 2012

Zone Valve?

Do you have a zone valve on the indirect zone? Is the boiler cold start? or does it maintain temperature? Is the grundfoss pump a 3 speed, if so what speed ?

If you had a Taco zone valve it could take up to 90 seconds to open, if the boiler is cold start the boiler water could actually cool the indirect until it came up to temperature.

I like to set the indirect to 135-140° and use a good mixing valve (honeywell) and use a pump for the indirect, no zone valve.

Slimpickins · February 2012

What Bill said

I'm with Bill on this one. I've found a few under performing indirects with the boiler supply and return connection reversed. Check out that possibility and check the thermostat too, just because it's new doesn't mean it's good.

icesailor · February 2012

Right & Wrong:

Some of you are right and some of you are wrong. I see this all the time.

The boiler is too small to heat the large amount of water he is trying to use. However, there is a solution. Which some of us use all the time. If you increase the water temperature in the tank (to say, 140 degrees), you theoretically increase the size of the storage tank. Then, install a thermostatic mixer WITH A %$^* MIXER WITH CHECK VALVES!!!! and your problems will be solved. A small boiler fired at .60 GPH will never have the ability to give you a large draw. But, extended over time, will solve your problem.

If you are using a triple acting control, and there is a low limit/circulator setting, and you set it at 110 degrees, and the boiler controls for the circulators are not wired through the famous ZC/ZR connections, the boiler will be running at 110. degrees until the circulator to the Amtrol gets a call. Turn the freaking low limit up to 140 degrees. It will become a new heater.

As far as a thermostatic mixer, I started to use Califfi because there are so many installers installing thermostatic mixers without checks, that wholesalers do not stock mixers with checks and they do not even carry in inventory of the checks that you can pop into the valves. You need TWO!!!! checks. If you have the cold water migrating into the hot through low flow, you only get warm water. With the Califfi, you need to purchase the checks as a seperate item unless they stock the ones with the checks. The Califfi's also come with a nice temperature gauge on the mixed outlet.

As a temporary measure, set your boiler control to 150 degrees with the high limit at least 170 degrees. Set the tank temperature at 140 degrees or higher, and try it after the system settles down. Then, report back on what happens.

If you have more than one circulator, and the ZC/ZR terminals in the control have no wires on them, and/or you have a Taco ZV controllers and there are no wires or jumpers on the ZC/ZR terminals, the boiler is wired wrong. Wire it properly, and you will think you just had a new system installed.

Also, good luck finding an electrician who knows and understands the functions of the ZC/ZR terminals. It's FM. Magic. If the electrician doesn't understand the magic, he/she is out in the pasture with the cows.

AND BE CAREFUL OF THE HOT WATER IN THE SHOWER. When you see that this works, set the limit stops in the shower valves so it doesn't get over 116 degrees. Until you get the rest of it fixed.

Al Corelli_2 · February 2012

I'm with Ice

Couldn't have said it better myself.

I have two of the 41 gallon Boiler Mates handling a 8 family apartment house. They NEVER run out.

What is the question of whether to use a mixing valve or not? I was under the impression that it was code.

We routinely run the tanks at 150-165. We always use a mixing valve. Always have.

hot_rod · February 2012

Assuming

it is piped, pumped and controlled properly a 115,000 boiler could to provide 3 gpm DHW near continuously. But it depends on incoming water temperature of course.

My Lochinvar 80,00 connected to a HeatFlow indirect will supply 105F non stop with a 3 GPM draw. My well water doesn't drop below 55F however.

Raising the tank temperature will provide more dump load but it will not change the amount of energy required for a continuous draw beyond the tank capacity.

Tankless water heaters work under continuous draw conditions, without storage, their performance charts show output with various draw and delta T.

hr

mplsheat · February 2012

Answer

Guess what??? The supply and return pipes were mixed up!!!! The installer wrote an "S" and "R" on the boilermate and this was the opposite it was supposed to be. Everything was based on what he marked on the pipes. ARRRRGGGG. I've been dealing with them for over 2 months. A simple googling the instructions (the instructions it came with didn't have the piping for the Double Walled model) and I found it didn't match up.

Why would this cause the heater to not work...isnt' just one big coil??? Also, it wouldn't have harmed the boiler would it have?

Thanks to all the suggestions...I didn't think they could have possibly installed it the wrong way.

billtwocase · February 2012

there ya go

makes you wonder what else may not be done to specs. Can you post some pics? I'm curious on how things are zoned

mplsheat · February 2012

Will post pictures tonight

Just saw this - I'll try to post some pictures tonight. I had talked to the technician throughout the installation and thought he was very knowledgeable, but it would be nice to get another take on things. Thanks!

Steve Whitbeck · March 2012

3 GPM

I still say the tank is undersized.

You guys are saying that the boiler is big enough to supply 3 GPM constant and I agree with that. BUT we are not talking steady state. We are talking starting with a cold boiler and piping. The boiler holds almowt 3 gallons and that doesn't include the water in the piping and the mass of the piping and pumps and fittings. The boiler doesn't allways start when the faucet is turned on. ALSO what happens if someone turns on another faucet in the house. The tank is too small. Should have been at least a 60.

Steve_152 · March 2012

boiler mate

gentlemen, please check your code books.....if this old guys memory not too tired, { my books are in office, & i am not going there right now } required to put anti-scald rated mixing / tempering valve at outlet of indirect.../ then you can run indirect at higher temp. & supply larger volume than tank capacity.../ agree with Al C. / just not saying the temp i set for tank...

Steve Whitbeck · March 2012

tank temperature

Yes i know the code on mixing ( anti - Scald ) valves. BUT I usually set my tank temp at 140* - any higher than that and the boiler runs forever to maintain this higher temperature. And we all know that anti scald valves fail. So in order to get higher volume out of the tank what would you set the tank tamp to - 160* ???

VERY DANGEROUS

hot_rod · March 2012

Be very careful

when you send temperatures above 120F to the fixtures. A good quality ASSE 1017 is a must at the tank. Thermostatic mix valves at the shower can be temperature and pressure type.

Always install thermostatic with isolation valves, they will need service from time to time. How often depends on how hard, how hot, and how many gallons flow thru the valve.

And beware of proper re-circ piping when using thermostatic valves to prevent "temperature creep"

Actually most injuries from excessively hot water are caused by the slip and fall, especially with the elderly.

hr

billtwocase · March 2012

I agree Hotrod

I don't agree with maxing out temp on an indirect to increase anything. If the tank is under sized, replace it with the right size, and run it at the safe and proper temps. Not all manufactures have given that way of thinking a thumbs up. Warranty's can become void that way.

Nick W · March 2012