Erratic operation of Honeywell HZ432 with York YZF/MV20
This system was installed May of this year. Cooling performed great ...no issues
Since the heating season has come and on 3 different days... one zone (same each time) runs wild and overheats
Let me set this up as to what I know from the customer and picutures they sent along and what I suspected and checked
3 zone wireless ( no outside RF interference suspected as customer who is qualified in the field of alarms knows his house)
no call for heat on all zones, all in heat only mode
heat pump is off when this happens
customer was not interfacing with control
fans on continous all zones
zone panel displays no call for heat of any type, on any zone, damper open on the zone that runs wild, other two are closed
aux heat is lock out until 35 deg f .... we have been above 35 when this happens, I tested and proved
thought it was not terminating defrost properly , checked and proven 3 times in a row last visit
So what happens the zone in question
-Damper is open
- other 2 close
- fan ramps right up
-electric heat strips energize
-no call for heat set point @ 68 room got as high as 80,
- only way to stop is to kill the power to AH and after its reenergized
system returns to normal operation.. AC even came on when the zone was in auto mode to cool the room
any ideas as to where to start ... I am not a parts changer
sounds like a fun call to be on lol. I'm suspecting if it was radio interference it would have done it with the cooling mode as well. Not unless customer bought another wireless device in the meantime which operates at same frequency. Lets see.. the damper opens and the other two close, electric heat energizes. It would seem there would have to be 24 volts somewhere . Something somehow is demanding a call for heat in that zone. I would start off by checking the setup programming in the zone panel. Make sure everything is programmed right. Check all stat wires. Maybe even disconnect the t-stat coming from that zone for starters?
after a long chat with honeywell tech support the plan is the next time it happens, is the customer is going to remove W1/E on equipment terminal strip. If the problem stops its in the zone panel. If it continues it in the equipment... wait and see
well that did not work....changed the board out yesterday morning after going thru the steps suggested. customer called last night at 945 same problem. had to sit in a dark room to calm down after that call
Originally Posted by JBocc
I finally got on site when the problem was occurring. I had fault code on the defrost control board indicating that "w" and "o" are present in heat mode. This error gives a soft lockout. 4 soft lockouts in a 12 hours goes into a hard lock out and locks out the compressor and switches to emergency heat . I checked for 24 volts at 'O" and there it was. I tried to isolate where it was coming from and a soon as I open that circuit it shut down. I powered everything down and back on. No 24 volt present on "o".... gone. No error codes. I cycled back a forth in and out of heat and ac. Nothing. Got on the phone with honeywell and we spent 2 hours checking for bleed voltage. We did prove the error code was correct as we put "o " to "B' on the zone panel that gave 24 volts to the "O" circuit. aux heat is lock out at 35 deg F which was proven and when I forced a defrost the error code came back. While Honeywell and York have been helpful...and both are pointing at the others equipment and in the same breath saying it could be their own. So I spoke with local branch manager and he offered to change out the boards under warranty(hate being a parts changer). I have also left O disconnected from the defrost control board and have put in series to ground a .25 amp bus fuse on "O". So should it energize again the fuse will blow and I will know there is still something going on.......FUN TIMES!!!!
Sounds like you got it whipped.
If u got o and w is it present to the zone board or just out of the board or not at all, this is easy to figure out when conditions are present. Could be board in cu or zone board or tstat or stat wire. U need to determine where o signal originates.
The defrost board can't open a zone. So it has to be in the panel. Or he has RF interference he doesn't know about.
Did you figure this out?
If not it could be wired incorrectly at the outdoor unit. I do not remember right now but it does have something to do with outputs maybe y1, y2 and w2. York had to send me a wiring diagram for the gas furnace to match up to the heatpump as the supplied furnace and supplied h/p did not show how to wire correctly.
my test fuse has been in for ten days and there has been no issues after changing the indoor and outdoor control boards. So the fused "o" to ground was removed last night and connected to defrost control board. No happy dance yet....just cautiously optimistic.
Well the saga continues.... since the control boards were changed. The erratic heat on has resurfaced. this time no fault code as was previously indicated. No call for heat at stats, zone panel showed no heat calls, heat pump was off, all zones were 3-6 degrees above set point, electric heat energized , IDF on high DAT 89F. )Measured at equipment terminal strip test point w1/e and w2 (jumped) to common from AH- 26 volts. Disconnected w1 wire from board to equipment- it de-energized fan and heat strip. Measured w1/e and w2 to common 0 volts , measured exposed w1 wire to common 0 volts.....WTF explain to me where the voltage went. As a test i am considering removing the zone control and going to a single stat... lock the dampers open to prove either controls or equipment because each are saying not me .. but then again.
Intermittent short in wires from heat pump to AH maybe. But doing your test is a good idea.
you need to call york tech support. The unit is wired wrong. what is happening is when aux heat is called for whether by t-stat or def. it is locking the aux. heat on even when the t-stat drops the call for heat the unit will still heat until it manually (Somebody disconnecting something) looses power . I believe you could say it is being kept on by a holding circuit. I am not familiar with york enough to remember what i did to correct the wiring. If your unit is not doing this I do apologize for butting in.