Munchkin LWCO

Jay_17

That is pretty much my thought for placement also, I am wondering if there is any advantage to supply vs. return, but probably makes little difference.
Thanks for anticipating my needs for control wireing, I had thought about it , but hadn't settled on the best place to interupt the system. putting it in series with the pressure sensor seems simple and correct.
I am debating whether to try to convince the inspector that the pressure switch is enough, but it probably is not worth the price of the LWCO to attempt it.
Jay

Jay_17

Where oh where

Ok, I am looking for opinions and/or experiences. My state requires LWCO on my Munchkin, I called HTP and asked if they have any recommendations on locating it, and they had no advise, so I am turning to you guys. I have baseboard below the boiler level, plumbed P/S in the preferred munchkin arrangement with zone pumps. I think it should be effective on the inlet side of the boiler, if there is no water there I am in trouble!
So where would you put it??
Jay

Guy_6

LWCO

Physically install the LWCO at either the supply or return nipple of the boiler.
Wire it in series with the water pressure switch,which is on the top of the left side manifold.It's a metal and white disc, about the diameter of a golf ball, with two red wires. If a low water condition exists, the LWCO will back up the low water pressure switch and shut the system down until the issue is resolved.
Ask the local authorities if they will accept the low water PRESSURE switch alone in lieu of a LWCO. The pressure switch will shut down the system before an actual lack of fluid will.
I am sure that Chuck @ HTP will respond here shortly as well.

Marty

Put mine above the boiler the internal pressure switch does shut off the munchkin before the lwco trips.

Chuck Shaw_5

LWCO

Personally, I would prefer to see the LWCO above the boiler, but the inlet of the boiler is the highest point. You can try to convince the local inspector that the pressure switch will act the same as a LWCO, however the company that makes it for us will not authorize it as such. I think, also, that the best place to break the internal circuits is the water pressure switch, as the fault that shows up, is directly related to a low water situation.

I personally like the McDonald-Miller RB-24, easy to use, and decent price. You will have to add a transformer to power the unit, as of now there are no provisions in the low voltage circuits for it.

If you have any additional questions, please feel free to call me on Monday, 8am-5pm, eastern, on Monday.

I was out of the office today, and I wasnt there to get the call.

Chuck Shaw
Technical Support Department
Heat Transfer Products
508-763-8071 ext 142

Jay_17

Thanks

That was one of the other options I was considering, if I put it up in the manifold (like the picture) it would be a bit easier to mount, and it moves the water line up above the boiler and primary pump.
Jay

Bryan_16

lwco

M-M makes a 120v model that you can use the line volatge to operate. The contacts are isolated, so you can still break the low pressure circuit.

Marty

Fault codes

One thing to consider The munchkins have a fault code for low pressure Most lwco's have a light so my thoughts were kill the boiler and pump and eleminate some potential troubleshooting issues in the future.