Moaning LP converted condensors

Unknown

I am assuming these are using a negative pressure gas valve with gas flow controlled by the combustion air blower? Do they have a throttle adjustment on the gas control or combustion air blower itself? If so what you are getting is an harmonic caused by the low flow relationship on the low end of firing rate. This has happened in the past on step opening gas systems and older negative pressure type controls.

It ususlly comes down to this: there has to be an adjustment made to the gas when it is at the low end to bring the pressure up slightly. A lot of the instructions will tell you not to touch the gas pressure to just adjust the throttling screw. In order to get rid of this harmonic you have to adjust the gas pressure. Set up with a gauge or manometer to measure the pressure. I would contact the two manufacturers for there recommend settings. It does not take a drastic adjustment and you have to be patient and sort of make very slow adjustments then check it and then if necessary another very slight adjustment. It is like adjusting a carborateur on a very precison engine.

If my memory serves me I discussed this with the HTP folks when I visited with them.

I noticed this is on an LP system so keep in mind the LP gas needs more air for combustion tham natural gas so make sure all LP setup has been followed.

I also find with the new burners used on the condensing units that the port loading on the burners them selves is not good for LP. The burners may need to be changed to a better port loading burner. Again the manufacturer should be able to help with this. I have modified some burners myself but do not recommend it unless you have had a lot of practice at that sort of thing.

Then again very strange two of you with the same last name with the same problem HMMMMMM very strange.

hr

Anyone else

having problems with 80K condensors moaning on low fire/ I have two different brands doing about the same song on low fire.

Sounds like somethinbg out of a horror movie. It may be if I don't get an answer

Gas pressure within range and stable. CO, Co2 within range. If you disturb the air intake while it is making the noise it goes away. It also disappers, on it's own, as the burner modulates up.

hot rod

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Paul Rohrs_4

Thought it was just me.

We have had two 80K boilers with the symptoms you describe. Everything checked out with CO and CO2, it was then and only then recommended that we adjust the Offset Screw to set proper fuel/air ratio. Problem went away.

To note on our last project, it was happening at "The Lighthouse" built in the glide-path of the airports runway. The HO thought the sounds were low-flying aircraft. It really is an interesting home. Here is a link.


http://www.capitolbeachlighthouse.com/



Regards,

PR

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hr

Good info, Tim

I installed an 80K Munchkin, an 80K Lochinvar Knight and an 80 Weil Ultra, last week and today.

The Munchkin needed 4 turns on the adjustment screw. Works fine without any noise or light off problems (Dungs valve)

The Lochinvar needed an orfice installation, very slight moaning.

The Ultra needed a burner tube replacement, orfice and new gaskets included. It moans loudly. The only info is to call the factory. Hard to do on a Sunday install. I will follow upo with the manufactures before adjusting the DO NOT ATTEMPT TO ADJUST screws Thanks for the info.

hot rod

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Plumdog_2

Moaning sounds

I have not had this with condensors, but have had it frequently when converting atmospheric type burners to LP gas especially at very high altitudes. I wish there was a definitive source for info in regard to high altitude combustion. Some of the equipment reps will just stare at you or shrug thier shoulders; others will not answer calls at all. I think some burners that are not adjustable for air just won't work at high altitudes. I know your not at high altitudes but I felt like venting.

Floyd_20

What happens if you go into the programming......

and set the low fire fan speed up a bit. I would be wondering how far up you would have to go to get the moaning to stop. I think the fan speed on low fire is 1200 rpm. If you adjust that to say 1500 does that stop it???? the 300 rpm would not significantly increase the low fire. Do you have the Gascom software that WM has, so that you can actually see in real time what the fan is doing? Also makes it very easy to make adjustments.
As I stated before I had a Ultra doing that and it was nothing more than the air being recirculated from the exhaust to the intake. Fixed it, solved it.

Floyd