Tankless hot water heater question

Nelson1221

We have an aging tankless water heater. Over the past few weeks out water will stop for a minute then come right back on. We've had the pleasure switch changed and now are wondering if it is the pump. But could it be the hot water heater. Could it stop cold and hot flow?

Teemok

How about some pictures and model number? A "pleasure" switch and pumps are not generally associated with tankless water heaters.

Nelson1221

Sorry typo pressure switch. Yes we are trying to rule out all we can before pulling the pump. Wondering if it could be the heater instead of pump.

Teemok

Is this unit connected to a storage tank? What does this pump you speak of do? Re-circulation line?

This is basic 80% tankless maintenance :

Inlet water filter

Igniter and flame rods cleaned. With a dollar bill. You will need gaskets.

Fire side of the heat exchanger cleaned

Proper descale. It might be very scaled up if regular maintenance was not done. There's a risk of HX tubing thinning or it being cracked. Re-circulating acid through it can expose or add to these faults as leaks. A long descaling flush can render a unit completely dysfunctional. Be prepared to replace when trying to make up for deferred descale maintenance.

Burners thoroughly cleaned of bugs, dust, and burner debris.

Blower fan cleaned.

Your symptoms are inline with a scale problem. The heat of the flame is not transferred to the water and parts of the unit overheat. It shuts down until it cools then fires back up to do it again.