PVS 50 Rheem water heater -pressure switch?

canpaul

Premium Member
Joined
Feb 12, 2011
Messages
10
Location
Ontario
Model Number
PVS 50
Brand
Age
1-5 years
Or power vented Rheem water heater will not light. This has happened very rarely since the unit was about 2 years old, now it is around 5. We would notice no hot water, and the LED on the control valve would be lit soild. Unplugging and plugging it back in would get it started again, sometimes for several months. Now it does not respond to a power cycle, so I looked at it closer last night.


When we power cycle the unit, the vent motor runs for several seconds, then the red LED on the controller goes solid, and it stops.

I checked all the controller wiring for continuity, including the harness that goes to the vent assembly at the top of the tank, all seemed fine.
I found that the pressure switch (pins 4 and 8) on the controller was open, which i guess is normal, but i suspect it never closes. After doing a power cycle, while the vent motor is running, if I short the pins on the controller that go to the switch momentarily, the unit lights and heats the water normally. I have cleaned out the area around the vent wheel, which was not dirty at all, removed the two hoses to make sure they are clear, and blew air through the hose nipples.

Is it a pretty safe bet to just replace the pressure switch at this point?

Thanks,
Paul
 

canpaul

Premium Member
Joined
Feb 12, 2011
Messages
10
Location
Ontario
Replaced the pressure switch last night. Mounted differently, but the heater is working properly now.
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
102,082
Location
McMullen Valley, Arizona
Hi Paul,

Sounds good, sorry no one replied. I know nothing about this model myself.

Jake
 

Vvarak

Premium Member
Joined
Jan 30, 2012
Messages
2
Location
Ontario
Replaced the pressure switch last night. Mounted differently, but the heater is working properly now.
Hi Canpaul,

I am having the same issue and need to order the part.
The switch is connected directly to the power-vent on the top.
And the part number on it is AP12839.
Doing a search on Rheem's catalog, the part number is actually AP12840.
Although, doing searches for these part numbers havn't returned any parts.

What part number and where did you order it from?

Thanks!
 

canpaul

Premium Member
Joined
Feb 12, 2011
Messages
10
Location
Ontario
Hi Vvarak.

I hope this is not to late to help you.

The part I ordered is "SP20111 Press Switch Kit W / Jumper, RUUD. I had to order it from a place called Wolseley Mechanical in Orangeville Ontario. They are a supplier of electrical and mechanical parts. I got their contact info when calling Rheem looking for the part. Of course Rheem does not sell parts to consumers. I paid $58.06 for the part.

Paul
 

Vvarak

Premium Member
Joined
Jan 30, 2012
Messages
2
Location
Ontario
Hi Paul,

I ended up playing the with sensor and it worked...until today.
This time I'm getting 3 blinks - "pressure switch closed" which is definitely pointing to the switch.
So thanks for the info!
I guess the catalog I was looking at has old part numbers. I found the part number you referenced in a newer catalog.
I called Wolseley in Oshawa and they gave me a bit of hassel that I'm not a contractor. But they quoted me $115.
I guess that's the "you're not a contractor" price.
I guess I'll call a few of them, as they are many in the GTA.

Thanks,
Henry.
 

dta721

Premium Member
Joined
Oct 30, 2012
Messages
3
Location
Ottawa ON
My 13 years old RHEEM HWT did not perform to spec :) in the weekend, the water was lukewarm during showers, also at kitchen sink.

I did some flushing every now and then, turn off power, gas valve, cold water faucet, empty the tank, then refill, to remove the sediments.

Called DE, a tech quickly showed up and fixed the problem satisfactorily on Monday. Great!

In the process the tech checked out the pressure switch, even short circuit it to verify it is working. However, it did not seem to close. He then verified the actual pressure IN and OUT using a meter, I forgot the exact unit, mmH2O, one of them was blocked. I don't know much about the complete circuit/functionality, observed that he simply gave the 2 translucent plastic tubings on top a ..."blow job" :)! That worked :)).

My point: given the 13 years of operation, there would be sufficient buildup (of sediments?) inside the tube connection, causing the pressure switch not working.

My 2 cents, hope to hear your opinions otherwise.
 

dta721

Premium Member
Joined
Oct 30, 2012
Messages
3
Location
Ottawa ON
I found my earlier post not very coherent, and in an effort to self study about this subject, I dug up some info from the web, happy to share it in a more complete way (note that my HWT is a high-efficiency without pilot light, as the ignitor control can only be on when all operating conditions are met):

Air pressure switches are used on (many) “fan assisted” gas fired water heaters to verify that operational conditions are being met; i.e. the blower is running or the vent/combustion air piping length is not excessive or obstructed.</SPAN></SPAN>

Air pressure switches are usually wired together with other switches into a “series” circuit such as the ignition control, which constantly monitors the “state” of the air pressure switch “circuit” -whether it is open or closed. As the blower starts and comes up to speed the normally open contacts of this switch should “activate” (contacts will close) in response to the pressure it senses.</SPAN></SPAN>

Normal Operating Sequence –</SPAN></SPAN>

1. At the beginning of a heating cycle the ignition control will verify the air pressure switch circuit is open before the control energizes the blower motor.</SPAN></SPAN>

2. After successfully completing the above open circuit verification step, the ignition control will energize the blower, the control will then check the air pressure switch circuit a second time after the blower is energized. This time the pressure switch circuit must be verified closed. The ignitor would not be energized unless this circuit closes after the blower is energized.</SPAN>
</SPAN>
3. The ignition control monitors this circuit during the entire heating cycle to ensure it remains closed. If this circuit opens (even for a split second) during the heating cycle; the control will close the gas valve and stop the heating cycle.</SPAN>
</SPAN>
By monitoring the air pressure switch circuit an ignition control can perform critical operational checks such as:</SPAN></SPAN>
1. Verify normally open air pressure switch contacts are not stuck closed or jumpered.</SPAN></SPAN>
2. Verify the combustion blower or inducer fan is running.</SPAN></SPAN>
3. Verify the vent/combustion air piping length is not excessive and/or obstructed.</SPAN></SPAN>

Credits: Paul Stewart</SPAN></SPAN>
Technical Training Department</SPAN></SPAN>
A. O. Smith Water Products Company</SPAN></SPAN>
Ashland City</SPAN>, Tennessee</SPAN></SPAN>
http://www.hotwater.com/lit/bulletin/tb-a023-06.pdf</SPAN>
 

Floorguy

Member
Joined
Aug 2, 2014
Messages
1
Location
Canada
Four year old Rheem Power Direct Vent was displaying trouble code for "pressure switch open when it should be closed". Blower motor running, but no ignition. After research including this site, opened the access panel on top of the tank where the pressure switches live. Yep, two switches. After the "gentle" mouth pressure check that the switches "click" on/off, I removed the hose from the housing of the exposed round pressure switch, and encountered water droplets in the hose.
Removed hose and switch. Shook water (assumed to be condensation) out of the pressure switch & hose, reinstalled and switched power back on. Burner lit and tank is running fine.

I have encountered this in a Coleman furnace as well: condensation collects in the hose and/or housing of this pressure switch: enough water collects, and the switch fails to respond to the air pressure differential and the safety feature does not allow the burners to light, as described above by dta721. Replacing the switch may be necessary, but shaking the water out can be an effective emergency solutio.
 

tgk

Member
Joined
Feb 3, 2018
Messages
1
Location
Michigan
Had some issue with my 1 year old Rheem Water heater Model # XG50T 12DM40U0 yesterday, the WI FI app notified me that the heater is having A006 Low pressure switch closed, with it 2 flashes upon start up, then the top vent started to move but stopped at about 40 degree, and 8 + 4 flashes turned on, indicating "Valve Fault Detected". I also noticed that the top vent seams is a bit wet. Searching the web found this site.
I used a blower to remove the moisture as much as I could. Reset the heater still resulting to same error code. Left it overnight with power on and adjusted the temperature 2 degree higher.
This morning it is back to normal operation! No error code!. > normal 1 flash. and Heartbeat - Alternate Bright Dim when heating up.
Based on this, I am suspecting the cold temperature condensate and dampen the top vent circuitry resulting to malfunction.
Hopefully this information is useful to some of you.

By the way, I also contacted Rheem and the web site is showing i am still in warranting. When calling Rheem at 1 866 279 4566. I was referred back to Home Depot where I bought the unit with extended warranty. Calling that number referring me to the generic 1-800 Home depot.. Need to find out what's going on here with all these diversion in case i have future situation!
 
Top