HVAC Site - Professional HVAC Contractors Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
I'm having issues with a Lennox 7.5ton 410a heatpump split system. This system has a dual evap coil ran by a single circuit compressor. My run pressures are way of at 60 low side and 310 high side, I have checked the lineset and expansion valves for any restrictions and could not find any. I'm not sure if my valves are sized properly, they are both 4ton and were installed during installation. Are these the proper size??
 

·
Energy mover
Joined
·
124 Posts
sounds like it's restricting volume. whats your superheat like? if your total superheat is low i betcha the one valve is starving its coil and then starving the compressor affecting the mass/flow rate. the valves are 4 tons each, if they're both 4 tons, then maybe one is feeding more to the one coil than to the other. check the independent evap outlet for hi superheat at each evap outlet to see if one is starving. i can suggest an EPR to even it out but perhaps splitting up the coils capacity like....3.5 and 3.5 or 3.5 and 4. good luck
 

·
Administrator
Joined
·
947 Posts
As above. Each TXV and its evap coil must be checked independently of the other.

You say its a heat pump. I'm guessing your running it in cooling mode. Are you?

Posting all readings can help us help you.
SH of both TXV's, SC at outdoor unit, and at the TXV's, Indoor and outdoor ambients.
CFM of indoor blower(not its blowing out good).
Temp delta across indoor and outdoor coils.
 

·
Registered
Joined
·
5 Posts
Duel evaporator split

Sounds like maybe one of the valves are not feeding like to see like 100 suction have you check ductwork? is the line set existing ? what size is the liquid line should be at least 1/2" .If it was existing check for hidden driers i have seen driers stuck in other spaces/walls .In like a mall one past tenant may have stuck the dryer away from the Air handler and the mall built a wall to split the space. Lennox had some major problems with parker TXV's a few years ago. check your amp draw on your blower adjust the shive and see what it does . If you haven't already instal service ports by the air handler . check the the bulb location and if there tight and wraped with cork/foam tape. It should be evident quickly where you problem is with that low of suction
 
1 - 6 of 6 Posts
Top