LP boiler

michael_4

Hello all,

I was checking a LP fired boiler the other day and the best Supply temp. I could get after 15 min. runtime was 100 deg. F.

The LP pressure inlet to gas valve was 11" w.c. and the tank outside showed 40% full. Valve was marked with conversion sticker. The outlet tap was sheared so no removing it and checking outlet pressure.

It was a Weil-Mclein.

Pump was B&G blue colored at 1/20 h/p. Sorry no model numbers.

I removed and cleaned burners, pilot assembly and heat exchanger flue passages with brush.

Any ideas?

Thanks in advance,
Michael

Bill de Jong

You may have 11" WC pressure but you are lacking volume. There is probably something blocking your gas line partially.Good Luck!

Unknown

Sounds like you

may have the wrong size orifices. Perhaps who ever converted it did not size correctly. How many burners do you have and what is the required input? Give me that and I will size them for you. Do you have an orifice drill kit?

If this is not familar to you then get the LP company to come in and check things.

hot_rod

too much load?

what's the boiler connected to? Any high mass system, radiant, cast radiators, etc can keep the boiler running cold at start up.

If there is a valve downstream from the circ pump try throttling it down and see if the temperature rises.

hr

Plumdog_2

Gotta know the outlet pressure

Like Tim says; verify that the orifice size is correct. You might be able to remove one burner, and slip rubber tubing over one orifice and get your pressure reading that way. The gas valve would have to have been converted to LP pressure, if it wasn't you will be way underfired. Be careful.

michael_4

Hello all,

Tim, there are 8 burners.

Hot Rod, 2 zones of approx. 50'each of 3/4" fin-tubed baseboard. Very small home(1700 sq. ft.).

I will advise client that we have several options. First will be read outlet gas valve pressure and see if orifices have number sizes stamped on them. If no marking will order new ones based upon load calc. and required fuel output. Then if that does not help we will look at clogged fuel line.

Thanks for your time guys,
Michael

Edward A. (Ed) Carey_3

Mike, a few questions

Mike,

Is this a new install or an existing system?

If it is new, then you have to large of a load, or the input is not adequate.

If existing, how old is it?

If it is an existing, did it ever maintain higher temps.

If it is existing and did maintain higher temps, what has changed?


Just a few things to think about

Ed Carey

Unknown

What is the input

give me that and the outlet pressure and with the eight burners I can tell you what size orifices you need.

michael_4

Mr. Carey,

This install is from mid 1980's. The couple that lives there have been satisfied with the boiler since they never turn the tstats above 64 deg. F. They told me if it becomes an issue of not heating this winter they would like me to follow-up. I would like to get a head start either way.

Tim,

When I call them this week to let them know what I have learned, they may ask me to return and get that info. and I will pass it on to you.

Thanks everyone for there input,
Michael