High Limit or Tricator

Gordy

Some quick preliminary readings on supply pipe out of the boiler indicate the temp gauge is reading closley to supply temp. Upon shutdown of the boiler the temp on the gauge climbs to 200*, and supply reading was 165 at shutsown high limit is set at 160*. I need to take some readings during boiler cycling on a call for heat.

Gordy

Gordy

High Limit or Tridicator

Got a little WM cga 5 in my rental house. High limit seems to be running erratic from setting according to the tridicator. Which is more likley to be correct or trusted the tridicator or high limit? Fouled probe on one or both the problem maybe?

Gordy

brucewo1b

An independant temperature survey is in order

That being said, if its the copper bulb type control they are off by 5-15 degrees a lot of the time but the newer electronic controls seem to keep a better reading on teperature, however gauges are off many times also.

Gordy

Bruce

Thanks Bruce that is what I'm going to do today, is take some temp readings. Just wondering if one part tends to fail over another. This cga 5 was installed in 97.

Gordy

tim smith

?gauge or limit

Normally the gauge is the culprit but you do need to double check. Tim

Timco

I have a CGA Gold (6) in my house, and the aquasat needs to be set to 200+ to get 180* water. The ODR now controls that, but it is definately the aquastat. My water temp readings are exactly what the gauge says. Like this since new 2 years ago now.

Tim

hr

trust neither

well type sensors really need to be installed with heat transfer grease to sense properly. It's rare to see a factory installed control with that grease, in my experience.Even so cap tube type sense elemete seem to vary a bit.

Tridicators depend on where they are located and if they were calibrated. To check one put the probe in a pot of boiling water. Then if the gauge reads low enough, try it in a glass of ice water.

I've found thermistor type temperature gauges to be the most accurate, if you insulate over them.

Those Azel dual temperature gauges are a very handy tool for checking temperatures and delta t's.

hot rod

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Gordy

Heat call cycle temps

Thanks Hot Rod I'm with you in thinking.

High limit set at 160*.

Couple of cycles indicate that the high limit is inline with supply temp comming out of boiler. Boiler shuts down at 160* supply pipe temp is 162*, while tridicator says 185*.

30* differential so boiler should fire at 130*. But supply pipe temp reads 124, and tridicator reads 135* when boiler relights.

So it would seem the tridicator is running wild with high temps, and closer readings at lower temps.

Kinda hard to compare pipe surface temp readings with a well type gauge though. Think I should replace them both so I can quit worrying about it.

Gordy