Heat Won't Increase

[combo1976]

My heat will not increase unless I turn the unit off then back on. Any ideas why?

[HayZee518]

we need make, model no, type [gas, electric etc.]

[combo1976]

It is a York Diamond 80 gas unit. Let me know if you need anything else. Thanks.

Pat

[paul52446m]

It is a York Diamond 80 gas unit. Let me know if you need anything else. Thanks.

Pat

does this unit have a glow bar or a sparker to lite the pilot?
Are you saying when you get it going that it comes up all the way to
where you have it set but then when temp. drops a few degrees that it won't come
You need to be standing in front of the furnace when it fires and tell me what it does. It sounds like at one point it is tripping off on safety. I need to now at what time it is doing this. Paul

[combo1976]

Correct. I have to turn the unit off for 30 seconds then turn it back on before temp will increase. I will check the other things you suggested and get back to you. thanks

pat

[combo1976]

It has a glow bar. When I turned the unit back on it started after 30 seconds. Temp in the house is set @68. Room temp increased to 68 degrees. The furnace stayed lit until the house reached the 68 degrees. After an hour or so the room temp dropped to 65 degrees and the furnace won't start back up without having to turn the unit off for 2-3 minutes then turning it back on.

[combo1976]

Also, I just went to increase the temp and the glow bar went on and the furnace started for 10 seconds then went off.

[paul52446m]

Also, I just went to increase the temp and the glow bar went on and the furnace started for 10 seconds then went off.

When you say the furnace started, do you mean the the pilot or burner came
on for 10 seconds. On a call for heat the inducer comes on for 15 to 30 seconds, then glow bar for 15 seconds or so then about 6 seconds of gas valve
opening. So i need to know a little more.
If the pilot lit for 10 seconds and then went out then it could be you need to clean your flame rod. If you look in at the burners you will see a thing that looks like a nail. If you have a pilot then it would be right there where the pilot flame would hit it. Even if the flame rod does not look bad, it can have a film on it.
Take some fine sand paper and clean it up. Paul

[combo1976]

the glow bar went on then the burners stayed lit for 10 seconds. I did just notice a red light constantly blinking in the furnance just now. I will look for the area to clean. Thanks

[HayZee518]

Paul, in use, doesn't the flamerod get sooted up anyways? It's always being impinged upon by the pilot and sometimes the main burner. Youll be cleaning that "nail" everytime!

[paul52446m]

Paul, in use, doesn't the flamerod get sooted up anyways? It's always being impinged upon by the pilot and sometimes the main burner. Youll be cleaning that "nail" everytime!

A flame rod gets a coating on it that you can't really see. it not soot.
A lot of service men do not know that even if it looks clean it will have this
chalky coating on it so it needs to have fine sand paper cleaning at least every
two years. If it is not clean then is starts to lose its flame rod electrical reading going back to the control. Flame rod readings are something that most service
do not check. Most of them do not have a tester to check it and don't know how to test it. Flame rod power can range any where from 3 to 30 Milli amps
Paul

[HayZee518]

do you know how a flamerod works?

[paul52446m]

do you know how a flamerod works?

Do you have a good definition for the flame rod? I know i was working on
flame rods many years before the came out on a furnace. The first ones i worked on was on big boilers. They used a Hon RA890 E and F controls
I know when testing them your readings would be from 3 to 6. The controls would drop out at about 2. So it was very important to clean the flame rod and the ground plain.. I think on the furnace you have a flame rectifier putting current down to the flame rod and the power goes through the pilot flame to the pilot head for its ground. I know if the pilot flame is not clean and making contact from the flame rod to the pilot head you will lose your ground and she won't work. Later Paul

[HayZee518]

the "blue flame" actually conducts DC current back to the electronics. before a flame impinges on the rod it has AC current on it. its called electrified rectification from a small surface [flamerod] to a larger surface [ pilot burner assembly]
I've worked on the honeywell purple peeper for many years in a textile company on their ovens. called a tenter frame.