My spa is kicking out black soot for black of a better word what is causing that

check gas pressure sounds like heater is sooted up and overheating get proper gas pressure then clean out soot on heat ezchange and you should be ok

check gas pressure it might be sooted up causing overheat

Hi, sounds like you could have an obstruction. Check the entire stack for bird nesting materials or debris. The propane, when it burns, should not produce any soot. My guess is that something else is burning in your chimney stack and if it is blocked, it will come into you room. Once you remove the debris, you should attach some wire mesh around the exit to avoid any heat seeking animals from nesting again. Hope this helps.

This will one or more things (1). You will need a manometer to check the gas pressure be sure it is at 11 inches of water collom. (27 inches in 1 PSI) at the back of the gas valve. (2) make sure you have good water flow. If you have an external by-pass this should be 80-90% closed. In the water manifold you will have an internal by-pass assembly this fine tunes the water you control with the external valve. (3) make sure you don't have any derbs around the base of the heater that will block air flow. Also be sure that your heater is away from any wall or has a draft hood.
Any one or more of these things will cause sooting. When you find the culpret and fix then you will need to clean and desoot the heater. Also to avoide this in the future you should have the heater serviced every year before you put it into service.
If you do this yourself be sure to use a plastic brush and not a wire brush as any little spark with the soot can cause an explosion.
This might be one you want to get a repairman involved with and be sure he or she is a profesional.

Soot is a sign of too much gas and not enough air. Have your propane supplier make proper addjustments.

3/4 pipe line will work and will keep heater from sooting up.

Black soot appearing above and around electric baseboard heaters is caused by burnt hydrocarbons in the air.
The Heating element draws the cool room air from the bottom and over the element. Any excess hydrocarbons in the air become burned and are deposited on the surrounding surfaces from the warm heated air flowing up out of the heater.

The Heater is not the cause of these hydrocarbons. They come from the home / enviornment.

Some cause.
Smoking, burning Candles releases waxy hydrocarbons, carpet cleaning solutions, spray type air fresheners.

Black waxy sooty deposits are usually from burning candles.

Posted by George Patterson