joev11
@comcast.net
| Rheem HVAC start up problem
I have a Rheem furnace and a Honeywell PRO TH4000 programmable thermostat. It is a brand new home and I am having a problem with the furnace as follows.
In the AM when the therm calls for heat, I can hear the furnace fire up. It will run for about 5-7 seconds and shut down. About 15-20 seconds later the furnace again fires up and sometimes it will stay lit and produce heat and sometimes it again shuts down. Eventually it fires up, stays on and works ok. In having the repair guy over he noticed that when we manually cycled the furnace a few times, only the first two burners would light and when the flame isn't spread the system shut down and recycled. This happened several times and upon checking the gas pressure on both sides of the gas valve and finding them OK, he called Rheem and was instructed to blow out the venturi and burner tubes (bear with me I'm not a technician and am trying to remember what he said he did). He then cycled the furnace manually from the emergency switch 20-25 times (according to him) and it worked fine. P.S. 2 days later, the same problem, start up, 5-7 seconds later a shut down and a restart. Additionally, twice even after the burners shut down the fan came on and stayed on for about 5 minutes after which it shut down and the entire cycle began again. In most cases the furnace eventually lights up and begins to heat but I am concerned it will fail completely at the worst possible time.
Rheem is coming here Friday 11/21 and any advice I can get from you folks would be appreciated since I would like to at least marginally understand what is going on here.
Thanks |
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zen1
@optonline.net | it seems you are getting the same problem with the venturi and burner tubes clogging, perhaps it's not getting enough fresh air, and producing soot, which clogs it.. rheem will let you know, just let them know you keep getting this problem.. |
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robbin
Premium,MVM
join:2000-09-21
Leander, TX
| reply to joev11
I had a similar problem with a Lennox furnace. This furnace was a normal efficiency (not condensing) furnace but it still had a fan assisted exhaust. There is a sensor in the ignition circuit that senses the amount of vacuum the fan is drawing. If it is not drawing enough it shuts the ignition cycle off. With mine the fan was producing barely enough vacuum for the ignition process to start but as the flames began they burned enough oxygen to trip the sensor and shut down the cycle. Troubleshooting this issue includes checking the sensitivity of the sensor and making sure that the flue stack is not partially obstructed (by a bird's nest for instance). In our case it was a design flaw and they had changed the specifications of the blower and sensor which required those items to be replaced. Obviously if your furnace doesn't have an exhaust blower then none of this would apply to your furnace. |
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joev11
@comcast.net
| reply to zen1
What's modd is the furnace runs fine during the day with the problem being at early morning start up after an extended "sleep" cycle as the temp set back takes effect. Even at that it is not every morning.
Thanks for the input. Anythuing I can use to convince the tech to do something is appreciated. My guess after all I have eread is the problem is some msort of blockage in the venturi. |
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zen1
@optonline.net
| reply to joev11
it should have a sediment trap just before the heater, to trap any junk getting into the heater, from the gas line, if it don't have that, then that could be the problem.. it's just a piece of pipe, maybe 4" long, with a cap on the end, at the bottom of a tee fitting.. all the junk should be trapped in there and not go to the heater.. |
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Stan3
@comcast.net | reply to joev11
I have a friend that has a rheem furnace but the electric pilot does not come on , but the fan runs what could be the problem. |
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tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
clubs:
 ·Verizon FIOS
| reply to joev11
Your setback thermostat has nothing to do with the burner firing, other than it calling for heat. The ignition system and gas valve are entirely seperate from the stat.
If you do not have a fan-assisted burner (ie.. chimney system) Then the problem may lie in the gas valve not opening quickly enough to light all the runners and burners. There could also be a problem with the runners between the burner that lights, and the ones that dont. Your original tech should have completely disassembled the burners and manifold, shame on him if he didnt. He should have swapped positions with the burners to try and chase the problem.
The other possibility is you have either a gas main regulator problem, or water in the gas service line. I have seen this cause intermittent problems. Check for a 4-6" round device attached to the left side of your gas meter, and make sure the hole (usually facing down) is completely unobstructed. This is the regulator vent hole.
good luck
-j
--
if it aint broke, tweak it!!
currently on FiOS (kick aZZ!) |
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tp0d
yabbazooie
Premium
join:2001-02-13
Carnegie, PA
clubs:
·Verizon FIOS
1 edit | reply to Stan3
said by Stan3 :
I have a friend that has a rheem furnace but the electric pilot does not come on , but the fan runs what could be the problem.
Depending on the age of the furnace, the pilot assembly may need cleaning. (should be done yearly by a service man) You can try to get in there with something thin and sharp, to clean the spark and sense rods. This would only be temporary. Make sure you turn the furnace OFF first.
If you dont have a pilot assembly, your furnace may have a bad hot surface ignitor. Usually these last 5-7yrs, depending on humidity and cycles. Again, time to call the service man.
-j |
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Stan3
@comcast.net | Thanx I will try that . I am use to lighting regular thermal couplin pilots on furnace but never worked on one with a electric igniting pilot . |
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joev11
@comcast.net
| reply to zen1
Rheem tech was here last week. He said the problem was the air intake tube was allowing in enough air but was allowing it in with to much force due to the 4 in opening. This excessive force disrupted the flame on the 1st 2 burners and would prevent the flame from spreading to the other 5.
By opening up another air access point it diffused the turbulence in the burner area.
Problem solved.
Thanks for all the input. |
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