LWCO Location Choice

D107

(See photos) Found an experienced contractor I can hire to add the LWCO and spill switch to my WM. We've eliminated the option of replacing the hi-limit with Hydrolevel combo limit and lwco. See photos for 2 suggested locations. One is in Zone 1 piping, but he found another location on the pipe holding the boiler vent; he could put a tee in and put the lwco in and then put back the boiler vent. I prefer the boiler vent option since less pipe cutting, but it would be a bit lower height than the other. I'd suppose the higher up the LWCO the more protection? Any suggestions?

STEVEusaPA

You could change the aquastat and probe and use one with a LWCO. While the system is drained, cut out the air scoop and install an air separator, then you can plug/ditch all those Taco Hy-Vents.

D107

Think I see only two vents--you're saying the air separator would make the other vents unnecessary...This particular tech has had malfunctions on two hydrolevel 3250s and is on his third one in his own home; feels maybe the computer within may be faulty. I don't have air issues at the moment--trying not to put too much $$ into this old unit.

EBEBRATT-Ed

Location looks ok to me

D107

@EBEBRATT-Ed thanks, so you mean either location fine?

HVACNUT

In the supply piping (location in the first pic) with a heel tee. I would also cut out the gate valve near the blue arrow and put in a ball valve.
The air vent location is no good. There's no water flow there and there will be air present. Air pockets kind of defeat the purpose of a LWCO.

D107

@HVACNUT Thanks I got the impression there would be a probe as part of the lwco that would reach down to where there was flow....but I'll certainly take this up with him, thanks.

HVACNUT

> @David107 said:
> @HVACNUT Thanks I got the impression there would be a probe as part of the lwco that would reach down to where there was flow....but I'll certainly take this up with him, thanks.

There is a probe, but its not gonna make it down into the block in that location.

leonz

I have a McDonnel & Miller LWCO that is wired as the first appliance prior to the triple aquaststat to cut off the power in the event of a low water condition.

In my case I have a 15 gallon steel expansion tank hanging in the ceiling above the boiler(I wish I had a 30 gallon steel expansion tank) and operate at a very low pressure feeding my baseboard heat(which I hate).

The McDonnel and Miller RB-122-E conductance type LWCO has a conductive metal tab that is submerged in the water supply and can be installed in a number of places-

1. steam chest
2. horizontal in riser pipe(in Tee)
3. vertical in header pipe(in Tee)
4. horizontal in header pipe(in Tee)

(Mine is is located in the base of the steam chest and is wired as the first control component to shut the boiler off in the event of a low water condition).

It may be simpler to just cut out a section of the riser and use 4 short nipples, a ball valve on both sides of the LWCO two unions and a tee for the LWCO if you use the RB-122-E in the example to be able to clean the submerged contact as required to maintain it conductivity every 5 years and reinstall it with minimal water loss.

mikeg2015

Most of your locations don’t make any sense as they are steam pipes.

Lwco needs to be same height as minimum permissible water level. Normally about 1” above bottom of sight glass.

mikeg2015

Look st the picture on this Crown boiler. Typical of electronic cut off. Not all boilers were designed for this type. They instead use float type normally integrated with the sight glass.

http://www.velocityboilerworks.com/product/bermuda-series-bsi/

Paul48

It's not a steam system

Paul48

It's late for this, but I have a problem with either location. The hy-hat on top of the boiler is a manufacturers requirement, because they know that air will accumulate there without it. In you first location, it's possible for the boiler to spring a leak, empty out and dry fire, because water is being held there by the flochek. And, by the way, the effectiveness of your air scoop is compromised because it is not plumbed according to the instructions.

D107

Thanks for these very astute observations Paul--all of which point to me putting the money into a new boiler. I have narrowed my questions to a few on a mod-con--and have a thread called 'Experience with Hard Water/Chlorides and Stainless Steel Mod Con HX?' for one of them.

Big Ed_4

Those two locations forget about .. The safety control can not be isolated from the boiler on an hot water system , That flow valve will cause isolation . Nor should an valve intended for furture service be installed between the low water cut off and the boiler .install first tap on the supply riser from the boiler or in the boiler it self..

D107

Even though for me at this point it may be moot, I had not mentioned in this thread that the original suggestion was to replace the white-rodgers 11B81-3 hi-limit in attached photo with a hydrolevel or hydrostat with an electro well that permits it to work as hi-limit and a lwco.