Adjusting condensate pump switches

Tim Melley_2

Thanks, Brad. It's more about a replacement boiler that keeps flooding, perhaps because the probe LWCO mounts higher in the WM Gold boiler than a float LWCO, and because the existing condensate pump won't pump in time, before the LWCO does its thing. In other words, this small system needs water before enough condensate collects to start the pump.

I'm hoping that I can adjust the pump switch to send water sooner from the condensate tank.

Anyone know of instructions for adjusting that float switch?

Fred Harwood_2

Adjusting condensate pump switches

Can, say, the smallest Hoffman condensate return pump switch be adjusted to operate more frequently for a small EDR installation? Have a situation where a WM Gold package probe LWCO begins feeding water before the condensate pump comes on, causing flooding.

Thanks.

Brad White

Curious

if your condensate pump is set up to be a boiler feed unit or not.

If it is a standard condensate receiver setup and releases because it is full (float control much as you describe), I would not use it for a boiler feed unit.

You simply have two disparate needs and actions in conflict with one side not knowing what the other is doing.

Yes, you should be able to lower the float switch level but the timing of that release is dependent on things not directly related to what the going on at the boiler at that moment. It may be needed, it may not be needed.

(You can illustrate this principle by drinking a lot of coffee or beer and taking a long car trip with your family through the desert or open prairie without a bathroom in sight.)

What I would do (ideally) is have my make-up water (if any!) sent to the receiver and have the LWCO low water signal activate the pumps as boiler feed pumps. This will also pre-temper your make-up water. Thus the response will be to boiler low water, not "full receiver".

I have to imagine from what you describe, that the boiler is under-sized and that the condensate unit is a way to compensate for that. Would this be the case? Curious.

Brad White

On many pumps

such as Skidmore and Flotronics, there is a float arm with a set-nut which determines actuation depth.

I do not think the elevation of your LWCO and water feed is so much the issue because it has to be on either side of the waterline wherever that happens to be. I do understand the operating situation you have but see it as a symptom you are chasing, not the cause.

When a boiler has a low water call (above the LWCO cut-out point but below operating water line) then I suspect that the boiler water content is fairly low compared to what it is serving.

By all means adjust that pump float on-point to be lower, but have it triggered by the boiler level control (LWCO output) first. You have the technology in place, I think it just needs to be allowed to give the right direction to the right device, your condensate pump.

Respectfully, that is my $0.02.

Brad

ttekushan_3

Good point on changing the control pattern on the pump.

The question to me is when the flooding occurs. If the flooding occurs throughout the cycle, then I'd say the new boiler has very low water content (and may even be too small for the job) so that the volume of the condensate receiver is proportionally too great.

If the flooding happens a while after the cycle ends then there may be a delay in condensate returning to the receiver. If there's a Float and Thermostatic trap or strainer on the way to the receiver, things will slow down a LOT.

Alternatively, if the boiler is new and impurities still in the boiler water are causing a wet steam problem, then the water level will decrease unnaturally quickly, causing the feedwater to come in more frequently than the stated steaming rate would indicate.

Even near boiler piping on a new lower water content boiler can make or break the timing of feed vs condensate pump cycles, particularly if the steam is "wet."

-Terry

Tim Melley_2

Switch setting

The Hoffman condensate return tank is 6 gallons, which is a lot of water for this WM Gold steamer, feeding perhaps 600 EDR. The probe LWCO in the package steamer mounts on the right side of the boiler face, just an inch or so below the embossed water level mark on the jacket. A float LWCO mounts on the left and lower tapping. It just seem too sensitive to the condensate return switch setting; when that box fills, it puts a quarter of a sight glass into the boiler in seconds, but long after the probe LWCO has had its say....

ttekushan_3

Feed Delay

have you set the feed delay to its maximum? There should be some DIP switches with instructions inside one of the covers.

Tim Melley_2

Delay

No dips in this one. Just a box with flashing red and steady green leds in the bottom. Would prefer an adjustable one, but that wouldn't get the condensate out of the Hoffman box for several cycles.