Rheem gas heating unit wont turn on. (Pics included)


  #1  
Old 11-05-14, 04:03 PM
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Rheem gas heating unit wont turn on. (Pics included)

Model: RRGG - 10E37JKR

Ignition module: Honeywell S8600H

Thermostat control: White-Rodgers 1F86-244

The unit was turned on for the first time the other morning and ran normally. It was shut off mid day, and when we turned it on at night it wouldn't turn back on.

I've included some pictures of the wiring, and was hoping that someone could maybe give me a few things to check (i have a multimeter) before i have to call someone.

Here are a few things i have done:

Turned off power at fuse box, pulled fuse at heater, and let it set for 30 minutes. Didn't fix anything.

When i turn the unit on, and set the thermostat to "fan - auto" and "heat", nothing happens except that a small fan turns on outside at the unit inside the service panel. The thermostat control makes a click to call for heat, but nothing happens except for the fan in the service panel running continuously.

Service panel fan

When i turn the thermostat to "fan - on", the blower on the unit will activate and it will blow unheated air into the house.

Service Panel

Ignition Module

Whatever this is

Thanks for any help!
 
  #2  
Old 11-05-14, 04:27 PM
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Can you get a picture of the "service panel fan" from a bit farther away? The picture you provided is too close up to really understand where the fan is & to what it is connected.
 
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Old 11-05-14, 04:56 PM
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First of all, I would be very concerned with the flex gas supply line inside the cabinet. In many jurisdictions that is not acceptable.

Here is a troubleshooting guide for your ignition module (first page):

http://www.parts4heating.com/v/vspfi...133-4001TS.pdf

The "service panel fan" is the inducer motor and closes a centrifugal switch that sends voltage to the ignition module.

The "whatever this is" is the fan and limit control. It controls the blower in heating mode and shuts the furnace down if it overheats.

I have attached a wiring diagram for your unit. The FDM in the diagram is the inducer motor. I suggest checking voltage at the FDR (forced draft relay), the FCC (fan and limit control), BR (blower relay) and the ignition module (PRC).

When the inducer motor is running do you hear the ignitor sparking? Set volt meter to volts AC and with the thermostat set to heat place one meter lead to the 24V (GND) and the other meter lead to 24V terminal on the ignition module.
 
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Last edited by firedawgsatx; 11-05-14 at 07:19 PM.
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Old 11-05-14, 09:01 PM
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Grady, the fan is mounted above the cream control with the brown knob, and it is pointing straight at the ground.

Firedawg, great info!! I'll get back in a day or so with some results.
 

Last edited by tiresharkdbb; 11-05-14 at 09:46 PM.
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Old 11-06-14, 09:52 PM
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OK firedawg, thanks to your post i may have narrowed it down a little.

First of all, i realized that the spark IS working at the unit. When the 'heat' is turned on, it sparks for about 30 seconds and then stops. There is no pilot light, only the ignitor sparking

I looked at the gas meter as the heat was turned on, and didnt see any of the dials moving.

Here are the readings i took as the sparker was firing:

24V gnd - 24V = 24

PV - MV/PV (both on the ignition switch) = 24

Using the GND (burner) as ground, i tested these terminals on the ignition module:

MV = 0
MV/PV = 0
PV = 24

Using the GND (burner) as ground, i tested these terminals on the cream colored module (is that called the gas module?):

MV = 0
MV/PV = 0
PV = 24

So maybe a bad gas module?
 
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Old 11-07-14, 06:29 AM
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With thermostat set to heat measure voltage ACROSS PV and MV/PV on gas valve.
 
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Old 11-07-14, 01:41 PM
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Copying my PM discussions in case anyone else needs the info in the future:

Originally Posted by tiresharkdbb
Yes i can see the spark firing.

I measured across PV - MV/PV on the gas valve and got 24 volts as it was sparking, then down to 0 after it stopped.


Originally Posted by firedawgsatx
Ok. When the ignitor is sparking do you smell gas? If not, I am thinking the pilot orifice might need to be cleaned. It has a small hole (only .020) that can get clogged up and not let the gas come out.

Another test you can do: shut down power to furnace. Remove the wires from the PV and MV on the gas valve. Set voltmeter to ohms (next higher reading than 200) and test across PV and MV on the gas valve.

No i can not smell gas. I took the pilot tube/orifice off and it seemed clean, i was able to blow air all the way through it.

Removed wires from the gas valve and across PV and MV it measured 1 (open).
 
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Old 11-07-14, 01:54 PM
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Can you post the model number of the gas valve?

Did you verify the gas valve is turned on? Do you have gas at any other gas appliances?
The fact that you have 24V across MV/PV and PV, are getting good spark and the pilot orifice is clean it points to a bad gas valve.

If you push down and wiggle where the wires attach to the gas valve while calling for heat do you get a flow of gas?
 

Last edited by firedawgsatx; 11-07-14 at 02:32 PM.
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Old 11-07-14, 03:43 PM
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Honeywell VR8204M 1024

The gas valve is turned on. We dont use gas for anything else in the house.

I jiggled the wires on the gas valve as it was sparking and nothing happened.
 
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Old 11-07-14, 08:46 PM
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Based on your testing, it appears your gas valve is bad. If the gas valve was opening you should be able to hear gas coming through the pilot orifice. If you decide to replace the gas valve I highly suggest you get rid of the flex gas supply line in your cabinet and replace it with black pipe.
 
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Old 12-21-14, 12:25 PM
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Here's an update for the thread.

Replaced the gas valve with a used one from ebay. This fixed the gas not igniting, but now i had an issue where the flame was chaotic and rolling out, and tripping the rollout switch constantly.

Inspected the heat exchanger and noticed a large crack in one of the cells. Ordered a new cell and replaced it (which was a chore and a half).

After the heat exchanger was fixed, i still had the rollout issue. I clocked the meter and realized that it was overfired... the firing rate was 120 Btu/hr, and the furnace was rated for 97 Btu/hr. Thought this might be the problem, but when i tried adjusting the pressure regulator on the gas control valve, i found out that it was broken and wouldnt adjust the pressure.

Ordered a new gas control valve, and it fixed the rollout issue upon installation. I clocked the meter to check it, and saw that it was underfiring slightly, so i adjusted it up to the proper firing rate for my unit. Have had no problems with it since then.

Was a long process, but very satisfying to get it working. Only thing that stunk was losing $50 on the used part. The guy (i think he was a hvac technician) had a 14 day return policy on it, but since i didnt try to adjust the pressure until i had finished the heat exchanger project, it was about 3 weeks before i realized it had been shipped defective, and he wouldn't refund. Oh well, that's how it goes.

Thanks for the help everyone.
 
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Old 12-21-14, 12:37 PM
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Good job!
I am happy that it all worked out well for you!
I am now laughing at those who were saying (on the other forum where you posted your saga) that you can blow yourself up and all that crap.
They make it sound like this is rocket science and it is far from it. With all due respect for the pros who get paid for what they do, I hate the "pros" who try to mislead you when you try to DIY by saying that you don't know what you are doing.
 
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Old 12-21-14, 01:04 PM
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You really stuck with it.
 
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Old 12-21-14, 02:54 PM
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@PJmax: Yeah, i was really relieved to get it fixed after all the time i was spending on it. Replacing the heat exchanger cell was by far the biggest pain in the neck... there must have been 75 of those tiny little screws attaching stuff everywhere. Had to take off soooo much stuff just to get them out, then it was worse trying to get them all back in and situated correctly and sealed back up. i made sure to take all the cells out and really inspect them good, so hopefully they will make it till the unit gets replaced. it was pretty time consuming, but at least i know they are all undamaged.


@PF4DIY: Thanks man! Yeah that other thread was nuts, haha. That forum was really active that day, so I popped in hoping to get a really brief question answered quickly, and it turned into a huge deal.

In their defense, i believe the ones that said to stop messing with it were only looking out for my safety... especially since i showed up out of the blue talking about messing with the gas pressure, without any backstory about how knowledgeable i was about such things... so i can see how they might have thought i was too inexperienced to be doing what i was doing on first read.

They lightened up on that after a bit, and gave some really great information and advice, but it still turned into a big clusterhooha because some people (me included) like arguing about semantics. ah well, maybe it entertained some folks. haha.
 
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Old 12-22-14, 12:04 AM
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If you don't know what you're doing, it's true - you can do yourself or your property serious damage.

The worst people are those who think they know what they're doing, really don't, and just want to save some cash.

Personally I wouldn't mess with gas or venting - too dangerous if something goes wrong & no liability insurance.
 
 

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