Haywood T400 Heater problem

[skwellington]

My heater (Haywood T400) has started to rumble. It still heats the water, but it sounds like it is getting ready to take off like a rocket ship!
I thought there might be some stone stuck inside, but that doesn't appear to be the problem.

 

[dmanb2b]

Welcome to TFP

 

[Poolschoolgrad]

Rumbling, banging or bumping is normally a sign of inadequate water flow through the heat exchanger.

Here are a couple of easy things to check.
Be sure your pool filter is clean. If you are using a two speed or variable speed pump, adjust to higher output setting.

If the problem persists, contact your local service technician to check for blockage inside the heat exchanger.

Continued use of the heater with inadequate water flow could lead to extensive (expensive) damage to your unit. Have it serviced soon.

 

[JasonLion]

The most common cause of low water flow is a dirty filter. Cleaning the filter is a good place to start.