VisionPro IAQ + York YZB + PV8

[starbuck83]

Hi,
I'm hoping one the pro's can provide a little insight into a couple of questions regarding my setup.
Current T'stat is VisionPro (TH8320) t'stat No outdoor sensor)
York YZB HP (Hot heatpump mode is enabled and working)
York PV8 2 stage variable speed NG furnace

It's wired according to York's diagram ( doc number 036-33182-002-A-1007) ( which has the HP defrost board as "master" for lack of better word)

Problem : I have noticed that under certain conditions the HP AND the furnace run at the same time ?? If the system is heating ( hot heat pump mode is active ie. blower running on low speed) and I increase the T'stat temp 1deg C the Furnace turns on and they are both running at the same time. (The T'stat activates Auxheat) . This seems counter intuitive ? They should not run at the same time ?? The coolant piping at coil gets very hot during these episodes ( not surprising as the coil is being feed by two heat sources)so I can't imagine that this is the way it's supposed to operate ? ( For example it's 5degC out side and T'stat set point was 20C ( indoor was 19.5C )when I bumped set point up to 21C. Compressor running and the T'stat turns on Auxheat so they are both running at the same time. Shouldn't the Defrost board prevent this ? ( That's how the York guy explained it's operation )

I'm about to replace the VisionPro T'stat with a VisioProIAQ ( because I can't stand the damn clicking of the relays :-) and I've read that it would be better to have the IAQ control the system as opposed to the York Defrost board ??
Is this correct, and if so, how should the wiring be changed to accommodate this ? I take it I would need an outdoor sensor to start , but how to connect the HP to the furnace and EIModule to keep Hot heatpump mode and two stage Furnace operation ? Ie if the Defrost board controls Hot Heat pump mode won't putting the IAQ "in control" stop this from working ? Obviously I'm missing some thing... but hey that's why I'm here :-) ( Please be gentle)

A little back ground, ... my neighbor is a commercial HVAC guy who put the system in for me. ( that was a big mistake.... After he asked ME what Hot heat pump mode was I decided end his involvement in the project) I then had to pay an Electrician to bring the install up to code. Then pay a York installer to fix the furnace install (gas piping , low V wiring etc) Needless to say I can't afford $130/hr for him to work on a system he didn't seem to familar with.

I just need a little info so I can do this correctly and have the system function to it's full capabilites

Thanks

Gary

[dac122]

Is this something that just started happening, or has the system always done this?

In defrost mode both units will run together, but you'd notice the outdoor fan stop running during that period, and it would only last a few minutes. There really is no reason to have both heat sources running together, and there is debate on whether this might cause longevity problems with your compressor. So yes, I would correct the system from running both at the same time, except during defrost of course.

Before you go swapping out tstats I would try to understand what the system is doing.

[starbuck83]

Thanks for the reply I appreciate it. I've posted at various sites and your the first persjon to actually offer some info as opposed to the usual "call in pro"

Just started happening ?

Not sure , I just noticed it.
If I had the bonnet sensor installed, then I could see both the HP and the furnace running at the same time during defrost, but as they didn't install the "optional" bonnet sensor, that's not supposed to occur. (Well according to the York info states that )

It may be part of the a defrost cycle, as I don't know if the fan stopped during these events and yes, they are relatively short events ... say a few minutes. But it's triggered by me bumping up the T'stat while in hot heat pump mode. This would seem to be a software problem as the defrost board should not allow this. No bonnet sensor, no simultaneous operation ?
I too have read that simultaneous operation may affect longevity so I wondered why there was always the "rule" that a bonnet sensor must be installed in FFuel mode ?

I'm going to install the IAQ but initially wire it with no outdoor sensor and leave the Defrost board as the "master". Why ? Well I need to move the T'stat back to where my old T'sat was before the HP install. They moved the T'sat near the front door and two heat registers so it basically warms a small portion of the house if I don't close the registers which defeats the wjhole purpose of having a "central" heating system. Running 10 conductor wiring the old location is quite a chore so I will use the existing 4 wires that are behind the wall.
I'll study for the HP/furnace operation before I rewire/program to have the IAQ control everything.
I'm still searching for some info on how to keep Hot heat pump mode yet still have the IAQ control the switch over. I like the Hot heat pump mode, no cold air when it turns on. Be shame to loose that unless the IAQ can duplicate it. Unlikely as Hot heat pump mode dpeneds on measuring the liquid line temp to make it's decisions.

Questions , questions, I'm full of them


Thanks

Gary

[Jarredsdad]

Hi Gary,

Welcome to DIY. We are all Pros at somethings and DIYers at others it seems here.

While we do recommend calling in a Pro from time to time, it's not usually the first answer.

First, the VisionPro is a very tight stat. When you bump the set temp "up", the stat actually sees the space temp go down. It thinks the HP can't keep up and asks the furnace for help. This is why you get both at the same time.

The only thing the defrost board does with respect to the furnace is turn it on when the outdoor unit goes into defrost.

Can you post what these settings are?

0170
0200
0250
0350
0360


Also don't be surprised if I move this thread to Thermostatic Controls where it should be. For now though lets leave it here.

[starbuck83]

Hi Jarredsdad, thanks for taking the time to post. ( My pro comment wasn't directed at anyone here ( or anyone for that matter, just a little frustration on my part), I've asked this same question on few other boards and the usual is that's it's too complicated for me to understand :-) and I should have used a pro in the first place, even though I've had 3 different pro's in house already)

Well let's see
My settings are:
170 = 7
200 = 1
250 = 5
350/360 not available on my T'stat in it's current configuration.( I would think that's because there's no outdoor temp sensor)
The Defrost board in the HP should be taking care of those settings ?
I understand the T'stat calling for Aux heat but that output ( W1) is wired directly to the HP not the Furnace so logically it would be the Defrost board that is controlling/allowing both the HP and the furnace to run at the same time ? It indicates in the install manual that this is not supposed to happen without a bonnet sensor installed. ( I see no sensor anywhere on the output of the furnace/coil and there's definitely nothing wired to BS/BSG in the HP) )

The way it's currently wired, it sure appears that the York defrost board controls everything. It decides when to run the HP/furnace, ( when the T'stat asks for it) what speed the furnace runs at ( hot heat pump mode-- dependent on outside temp /line temp) etc.
W2 is connected only between the furnace and the HP so the HP seems to controlling when the furnace upstages as the upstage timer is disabled in the Furnace as per the HP install instructions.

Tonight I witnessed a defrost cycle ( at least I think it was def cycle)the lineset went cold and the furnace came ( for few minutes) on to offset the cold coil. The HP Fan shut off , there was a sucking sound and it went back to heating.
This is different from the dual heating events I have witnessed where the coil was being fed with hot refrigerant at the same time the furnace was running. Overall the system seems to function correctly for all other conditions, which has me puzzled.

I hope this doesn't come across as a rant or similar, I love my HP/Furnace and I find diagnosing fixing faults quite interesting.
I can't wait to install the IAQ and see what trouble I can get into ( I'm kidding of course)

Sorry if I posted this in the wrong section, I thought it was more of system problem as opposed to just a T'stat issue.

Cheers

Gary

[dac122]

Gary,

Your posts are long but full of good detail. Keep it coming

Sounds like this is not defrost and you've got something else going on like your system is too sensitive to increases from the tstat as mentioned. It is possible you're somehow wired wrong. Check out this post it might shed some light.

Curious, what happens if you go to em/aux heat. Does that run just the furnace, as expected?

Your tstat settings look correct after reviewing this. Without an outdoor sensor, I think you're right, the HP is making all the decisions. So we need to figure out why the HP is bringing on your heat from the HP's controller perspective. Your first upgrade BTW should be an outdoor sensor so this or any other tstat can make all the decisions for you.

I'm looking at doc 036-33182-002-B-0108 (can't seem to find your doc, but I think this is close). Which wiring configuration do you think you have in that diagram, or can you dictate wire colors from tstat to air handler to HP? Do you have the YorkGuard VI control module? We may need to understand how that baby works to fully understand how its reacting?

I would emphasize again not to just replace the tstat until you know that will help. Once you understand your system and/or understand what's going on, you be in a better position to do loads of upgrades. Whatever you do mark things, take pics, etc. so you can put things back the way they were in case something doesn't work.

After that have all the fun you can stand. Just don't let the romance get in the way of other relationships. I know what you mean about HVAC, for some reason I find its complexity addicting.

[starbuck83]

Hi dac122, thanks for the reply.

You're definitely not the first to call me "long winded" :-)
There's only one way to describe something.... in infinite detail ;-)

IT has the YorkGuard VI Demand defrost board although I can't say if it's the new or old version. ( 069 vs 080) I'll have a look tomorrow.
EM heat selected on the T'stat has only the furnace running.

I see T'stat Aux heat indicator come on at various times , but it seems to make little difference to system operation, it' definitely the Defrost board controlling everything.

Seems York updated the low voltage wiring so your drawing number is more recent than the one I referenced
It's wired as per HP15A ( PV8 with YZB Hot heat pump enabled) I've triple checked the wiring from top to bottom.

I have an outdoor sensor on the way, but I'm still unsure how to add it ( for control purposes as opposed to just a temp indicator ) without loosing Hot heat pump mode.

I've fully documented the install with Pic's diagrams etc. (I'm a stickler for details , but do you think I wrote down the version number of the Defrost board ? DOH !)

Cheers

Gary

[dac122]

I must admit to being a little confused. On the one hand you say you only have 4 wires from your tstat, but diagram Hp15A shows more than 4 needed.

What colors and what terminals are connected to the tstat? And have you tried to see what is energized before and after you push the tstat up 1 degree when it brings on your aux?

[starbuck83]

dac122,

mmmh I don't recall saying/indicating that I only had 4 wires hooked up ? I did mention that the New IAQ would be installed where the original T'stat (pre heat pump install) was located because the current visionpro was installed right near the front door and 2 heat registers. ( There are only 4 wires where the old T'stat was so the IAQ solves 2 problems. I can move the T'stat back where it should be (without having to pull more conductors)and I don"t have to listen to the relays clicking as they'll be in the EIM on the furnace.

Just to clarify, the system is wired as per HP15A with one exception, L is not hooked up between the either furnace or the heat pump. That would have required 9 conductors at the HP and they only pulled 8 conductors. ( Quote" Oh no-one hooks that up because it's just confusing for the average homeowner ... it's not needed") Ya, I can see why no-one would want any error reporting I'll either run another couple of conductors or just replace it with 10 conductor plenum cable. Then I can complete the wiring (L) .

I've checked the T'Stat outputs and they operate correctly for what's indicated on the display. EM heat, Aux heat, heat, cooling etc.


I did find a new PDF for the Defrost board that now makes reference to the HP and furnace running together ( for 30 sec) if the outdoor temp is below the BP but above the LTCO
but further down it states that the HP and furnace will not operate together without a bonnet sensor installed ?? seems contradictory to me.

I'll do some more reading tomorrow.

Gary

[dac122]

Okay sorry, my mistake you do have 8 conductor. That makes perfect sense. There are setups where you can run less conductor and the tstat is a type of remote. But I digress...

So what I am curious now is what is energized at the tstat when HP only is on. I'm betting Y and G (O/B should be energized for cooling). Then when you increase temp, by the 1 degree that brings on the furnace, what is energized then: E, Aux, nothing? Do you know how to use a multimeter to check this?

This should give us a definitive answer whether the tstat has anything to do with bringing on your furnace. BTW this is a good exercise for your tstat upgrade.

Interesting about the BP and LTCO contradictions. But I believe you're seeing your furnace and HP on together more than 30 seconds. Correct? Just curious what are your BP and LTCO set to?

Yeah, I'd want that L wired up. Put that on your list. If we follow that thinking we'd have to ban all Check Engine indicators.