Lennox 3ton Rooftop question.

[budman21901]

I am attaching a PDF of the actual unit specifications. Thanks everyone for the replies.

http://home.comcast.net/~budman21901/lennox.pdf

[AiResearch]

budman if you get some time, do some reading on thermal expansion valves and how they work

you will then see how, if a power element and sensing bulb were to loose some or all of its charge, or experience some other type of problem, it will fail to open the valve enough, or at all, resulting in low evaporator pressure and high superheat

the power element / sensing bulb can be replaced without removing the valve itself on that Sporlan that is in the unit you are working on

there is a fair chance that is your problem IMO based on the info you have given and experience with that equipment

good luck

if this unit has the humidity control option with reheat coil, there could be other issues

[budman21901]

budman if you get some time, do some reading on thermal expansion valves and how they work

you will then see how, if a power element and sensing bulb were to loose some or all of its charge, or experience some other type of problem, it will fail to open the valve enough, or at all, resulting in low evaporator pressure and high superheat

the power element / sensing bulb can be replaced without removing the valve itself on that Sporlan that is in the unit you are working on

there is a fair chance that is your problem IMO based on the info you have given and experience with that equipment

good luck

if this unit has the humidity control option with reheat coil, there could be other issues

Thanks for the info. No there is no humidity option. I know exactly how a TXV works. They are just not called power heads here, or i have never heard them called that. Diagnosed them many times, I see your point though. It very well could be a TXV issue. When the extra refrigerant is introduced into the system it stays stuck dropping suction pressure, and causing the restriction. In low stage blower is on low, and Condenser fan is on low, and comp running at 67% Problem is unnoticeable. I checked that TXV, but is it opening enough?? I like that diagnosis much better then mine and i will triple check that TXV next time i am there.

I think new technology causes us to over think things, and not go back to the basics of refrigeration. Now i need to check that TXV more thoroughly because i can see exactly how that could be the issue! Thanks, and i will let you know..

[limmy09]

whats the time between stages, does it shut down or just kick in to high gear. what if the txv is not acting fast enough. are you putting in to second stage or is the tstat

[budman21901]

Sorry for not getting back to this earlier. I moved so i have been busy and just got internet hooked up at my new house. Anyways, i replaced the TXV and it solved all the problems. The TXV must have been stuck just enough to allow movement in first stage, but when second stage kicked in and introduced refrigerant capacity the TXV just didn't open and suction would drop off. TXV was the issue, and thank you for all your help..