Carrier Weathermaker 9200 Pressure Switch

My furnace (Carrier Weathermaker 9200 58MXA 060 F S/N 1101A10074) had a bad pressure switch. Was receiving a 31 code, called Furnace Repairman. He said everything looked good except the switch, he showed me that sucking/blowing on the rubber tubing to the switch unfroze it and to call if it continued to be problematic. I called and was quoted an additional $280 so I replaced the pressure switch myself.
The original was metal and the sticker read HK06NB120. I took it to Sears, they looked it up and said that it had been replaced by HK06NB124. The replacement is a cheap plastic part and I have my doubts that it is the correct part. Can anyone tell me what the correct pressure switch part # should be for this unit?
Also, furnace seems to run fine except for the period bringing the house back up to warm after turning the Tstat (Honeywell Magic Stat/32 CT3200) down to save energy. Does the following look like normal operation for this unit? or would this fit into the category of short cycling?
Below is documentation in minutes:seconds from start, raising temp from 56F to 61F with an outside temp of 32F.
00:00 Inducer ON
00:42 Flames ON
01:45 Blower ON
18:24 Flames Off - 18 minutes of flames
18:43 Inducer Off
20:27 Blower Off
20:27 Inducer ON
21:09 Flames ON
22:14 Blower ON
29:22 Flames Off - 8 minutes of flames this time
29:22 Inducer Off
30:58 Blower Off
30:58 Inducer ON
31:41 Flames ON
32:46 Blower ON
41:09 Flames Off - 9.5 minutes of flames this time
41:25 Inducer Off
43:22 Blower Off
43:32 Inducer ON
44:14 Flames ON
45:20 Blower ON and now up to 61F

This is my first house and I'm paranoid that my furnace isn't functioning properly.

Thanks in advance for any help, or words of wisdom.

 

I would not buy components for a Carrier furnace from Sears.
But since you've done this already, if it is doing its job leave it, unless of course you can return the switch and get your money back.

If you opt for buying the right part, let me know. Totaline is the official parts store for Carrier.

Regarding the cycling, I can't tell you if the thermostat is what is doing it OR if perhaps is the limit switch that is causing it. To be sure, here is what you should do...

1- remove the thermostat (not the subbase, only the thermostat), so that you can see the thermostat wires connected to the various terminals in the subbase.
2- put a jumper between terminals W and R. This will start the furnace and keep it going non-stop.

If the furnace runs for sometime and still shuts itself OFF, then you probably have a limit switch problem. But if it keeps on going and going, then we have to look at the thermostat.

I'm not saying at this time that the thermostat is defective...I'd have to do some reading to find out about proper programing and the features it may have that cause the cycling you report. But honest, I do not see short cycling here. The thermostat may very well be doing its job the way it was built and told to do it.

 

If it is not below 0 where you are at, I am curious as to why your furnace no sooner shuts off and then it tries to start up right away? I mean right away. Does your house leak a lot and/or lacks insulation or has poor windows and lots of them or ?

 

Ecman:

I think that what Neil means is not that the t-stat reached its setpoint at the end of the first heating cycle of 18 minutes, but rather is cycling two more times altogether (2nd cycle lasts 8-mins, 3rd-9.5 mins) on its way to bringing the temperature up to setpoint.

I may be misinterpreting, but if not, I think that's what he means.

 

You are right. I read the post too fast.

 

pflor,

Thanks so much for the quick reply.

I went to the Sears Home repair center with the original part in hand and put it on them to order me, hopefully, the correct replacement. Had it not worked, I could have returned it, I think. If I had ordered the wrong replacement online myself, I figured that I'd be unable to return it once opened and tried.

I just noticed the short heating cycles this past weekend and stumbled across this site while looking for info. Reading posts about short cycles and what not had me thinking I had a problem, possibly caused by me using a wrong pressure switch. I never thought about it being the t-stat.

Anyhow, last night I went to jumper the t-stat as you suggested and upon pulling the t-stat saw instructions on the back pertaining to high efficiency furnace (90 or 91+ AFUE) settings. I unscrewed the adjustment screw 1 turn as specified and the furnace then ran with heating cycles of 25 and 20+ minutes vs. the 18 and 8. I'll keep an eye on it and if the 25/20 was just a fluke, I'll try the jumper and report back.

Thanks again.

 

beautiful!
You do not need to try the jumper test anymore. A heating cycle hovering around the 20-min mark is pretty good. There is no short-cycling issues here.

Short cycling could be ascertained should the ON and OFF sequence happened at intervals of 5 minutes or less in a situation like the one you have at home.

You did not have a short cycling issue there to begin with, and how that you have adjusted the t-stat to its rightfull settings things are even better.