variable speed temporary control

rick in Alaska

I have a customer who has a Tekmar injection control that died and we are trying to get the heat back and operational. The control is of course only special order from the factory, so they have to wait a day or four before sending it, then have to ship it cross country to be put on a boat to ship up here. Or spend $100 or so on the major shipping company. Anyway, it is because of customer finances coming slow method and won't arrive for at least a week.
I got called in to look at it after their electrician diagnosed the problem. He hooked the injection pump up to line voltage and is just letting it run. The problem is the heat going to the floor is running in at 160. I know I should be able to put on something like a variable speed fan control and just dial the pump down to maintain a low temperature, but not sure what kind of control will work with the pump without causing any issues. Pump is just a 15-58.
Thoughts?
Rick

SWEI

Any decent inductive rated lamp dimmer will work, but you will not be able to turn down much more than 50% (possibly less, it really depends.) Make sure you start at 100% and work down from there. Once the motor stalls, give it a couple of minutes' rest and then start over at the top.

rick in Alaska

The lamp dimmer I can get right away, so will give it a shot. I think if I can slow it down by half it will probably be ok. I will see what happens.
Thanks a lot.
Rick

hot_rod

choke down the flow will help some also. Lower the boiler temperature as low as possible.

You want an electronic "triac" type dimmer. The old rotary resistors will just reduce voltage and cause high amp draw, the motor may not like that

SWEI

Not sure what you mean by rotary resistor, but non-TRIAC lamp dimmers are rare as hen's teeth (outside of a few recording studios.) The important thing is to get a dimmer rated for inductive loads (typically used with landscape and other low voltage halogen lighting, sometimes for ceiling fans.)

Gordy

Yes using a light dimmer switch to try and control a ceiling fan produces a hum when trying to slow the fan motor down. Use a fan speed control switch.

Gordy

Another option is a router control to make a fix speed router variable speed. Got a menards up there they have them.

rick in Alaska

I will see what the local hardware store has available. I think they have dimmers. As far as any other options, It is 90 miles to the closest Home Depot, but that may be an option if I have to.
Thanks very much for all the info guys!
Rick

ratio

Is there anyplace that's not 90 miles away in Alaska?

On a perhaps more helpful note: Perhaps an electrical supply house would be closer? They'd certainly be able to get a stout fan controller, & possibly have one on the shelf.

Mark Eatherton

If it were me, I'd manually choke flow on the VSI transfer loop pump, and then install a strap on aquastat on the RFH supply setting it for its maximum allowable supply temperature, and cycle the injection pump OFF when the supply water going to the RFH circuit is at its maximum.

Sweet, simple and safe...

ME