Boiler BTU size and combustion testing

markurl

Hi everyone. I had a Carlin EZ Gas installed several months ago by a plumber who clearly didn’t know what he was doing. I contacted another local, reputable company to troubleshoot it and I am concerned it was not done right. The new tech used a 3/16 drill for the orifice which appears to be way too low for my boiler (burnham mpo iq 189). When I google search it, the boiler appears to be 167k BTUs. He said he is firing at 100k BTUs. Am I crazy? Also, the combustion test results all look fine except for the stack temp (203F). I read it should be over to 300F to avoid condensation. Any help or suggestions would be excellent.

Below are links to pics that should help.

https://ibb.co/w7035mz https://ibb.co/NCJgb0x https://ibb.co/nDxKB9w

STEVEusaPA

Well you know Burnham isn't going to help you. You should try tech support at Carlin.

You're severely underfired. What was the manifold pressure, if anyone bothered to check? The orifice probably should be something more like 3/8", but don't change it without and experienced competent pro there. Orifice, manifold pressure, and air band all have to be adjusted together with the proper tools (and know-how).

Depending on your location, Carlin's man in the field could hook you up with someone more familiar with setting them up and testing them. That tech on site, with an analyzer and manometer, talking to Carlin , will be able to make sure it's set up with the right orifice, air shutter setting and manifold pressure.
Currently Carlin doesn't offer (didn't test) an EZ burner with the MPO, but it doesn't mean they can't make it work (unless they did test it and it didn't work).
203-680-940, they should be able to point you in the right direction.
You can also wait to see if either @Steamhead or @Tim McElwain respond to this thread as they would have the most experience with these conversions.

markurl

Steve,

Thanks for the reply. The tech stated the reason for under-firing was to make the combustion test not elevated. Can you effectively under-fire a boiler? I know he was on the phone with Carlin; however, this still feels wrong to me. I hate to ask an ignorant question - but what is the manifold pressure?

ch4man

your combustion numbers are off. CO, O2, CO2 all say properly fired, but your right flue temp is too low.
what was the boiler water temperature when tested? that will have a larger effect of flue gas temperature than the other CA numbers

markurl

Ch4man. I don’t know what the water temp was when testing. I contacted the installer and asked that he research the low stack temp reading.

Steamhead

It's underfired. Have the tech come back and drill it out, then test it again. I'd start at 9/32" and go to 5/16" if needed, but that's just me. Stack temp should be over 325° F, and a bit more wouldn't hurt.

What diffuser (firing head plate) is on that burner? It should be a 9-slot one.

Does the chimney have a stainless-steel liner? It should, with low stack temps like this. Also, the barometric must be a double-swing type which is required for gas firing, and it must have a blocked-flue switch wired to the burner.

Burnham gets a hissy fit when we talk about firing these boilers with gas, but if done right there should not be an issue. @Tim McElwain has converted thousands of boilers and never had an issue, and I listen to him because he's as good as it gets.

markurl

@Steamhead the diffuser plate is B. The quick guide says that is ok. Would that be sufficient? The metal flue stack for the boiler is entirely separate from the wood burning chimney. The original installer added the double swing barometric that is wired to the Carlin burner.