Does the Laars Endurance EBP 110 circulator pump modulate its speed according to the flame output?

Chris Alonzo

The voltage going to my circulator keeps changing and it even goes down to 14V sometimes, causing the boiler to kettle. I was wondering if the cause is a bad boiler control or a bad PWM (modulator) board.

hot_rod

Read through the manual, I don’t see any mention if the pump being variable speed

The label on the pump does it indicate VS
IT would have 4 wires is it is a 0-10vdc controlled pump. My Lochinvar has a Grundfos VS circulator m, 4 wire.

It could be a standard PSC circ controlled by a triac for speed control.

If this is the model you have?

https://www.laars.com/images/uploads/products/1117F.pdf

Chris Alonzo

That is what I have. The circulator is a Grundfos UP15-42F. It is a 2 wire 120VAC motor. 

hot_rod

Sounds like a standard circ, unless I’d shows MixiMiser which was a VS circulator, generally black in color with a much larger terminal box.

If it is being controlled by a wave chopper or triac, I don’t think you can read that output with a standard voltmeter