I just had a new raypak 400k cupro-nickel natural gas heater installed to replace my old Laars unit...the old heater would not fire if there was not flow through the heater. This new heater seems to not care if there is flow or not; when the heater was installed, I had the installer put in a couple of valves so I could isolate the heater when I need to lower pH for AA treatments, and when I isolate the heater, it will still fire when I expected it to error out due to no flow. Does this heater behave differently by design, or is something wrong preventing the flow sensor from stopping the heater from igniting?
Heater should not fire with no flow, right?
- Thread starter gilbee
- Start date
That heater should NOT fire if there is no water flow. Now, if you isolate the unit and don't drain the water out of the header there is enough pressure inside it that it would fire. So when you isolate the heater with the two valves, drain the water out of the header and then it won't fire.
Ah...ok, that must be it, I didn't drain the header (and won't in this case, since I'm only doing it temporarily)...thanks!
If I remember right there is a setting for the flow shutoff when you set it up. I remember reading about it in the manual but when I shut the flow off my heater turned off so I didn't have to mess with it.
Note that heaters don't have a flow detection ability. They detect pressure. Therefore, they can fire with no flow as long as there's pressure.
I think that all heaters should come with flow switches. If swgs can include them, heaters should be able to as well.