Why did they do it this way?

RayWohlfarth

Greetings

I was consulting on a local steam project in a school and ran across something that confuses me. The installers mounted the pressuretrols remotely on the steam header. There are 3 boilers. I see 3 modulating controls and 3 auto reset pressure controls. My question is, why would they do that? Most modulating controls are mounted on the boiler. Perhaps it's easier to get to the controls. I was thinking that perhaps they didnt want the controls to modulated back until the entire loop had steam but not sure. I would love your thoughts. You can see the boilers in the background of the pics Perhaps @retiredguy knows His company did it this way. Thanks

ethicalpaul

 I was thinking that perhaps they didnt want the controls to modulated back until the entire loop had steam but not sure.

The only way I could see this being the reason is if there were steam valves at each boiler that could isolate it from the others.

Otherwise, if it was for this reason it was misguided. The pressure measured at all three connected boilers will be the same all the time no matter how many of them are making steam or where they are in the steam-making process.

EBEBRATT-Ed

Looks like Power Flame Burners with Smith 4500??.

The modulating controls on the header are fine. They are not limit or safety controls, so they don't have to be on the boilers.

In fact, Honeywell used to make a series 90 control for 2 boiler that could modulate 2 burners with 1 control, so it had to be on the header.

As far as the other pressure controls I suspect they have a 3 boiler lead lag system to stage the boilers. Probably a "Preferred Utilities" control.

In fact if you blow up the picture of the controls you will see that the three controls are set at different pressures.

The boilers (I hope) have manual reset safetys and auto reset safetys on them in case the stop valves are closed in addition to the header mounted stuff.

This is a common set up to have lead lag controls header mounted for multiple boilers.

Usually the MOD controls are on the boilers but since they are not a safety it doesn't matter

If it was me I would get the sealtight up off the bare header befor the wires cook but thats just the electrician in me.

Missing box cover code violation!!!!!!! LOL

mattmia2

It is more convenient, you can leave room to unscrew things for service and certainly is easier to weld a bunch of bungs on the header than to try to pipe all 12 controls off the boiler.

RayWohlfarth

Thank you sirs. I appreciate. I was just curious because I haven't seen it done this way since. yes each boiler has an operating and a MR limit

ethicalpaul

Is there an automatic steam valve on each boiler? If so I rescind my earlier comment!

EBEBRATT-Ed

@RayWohlfarth Just curious do you know if it has the lead lag controls?

RayWohlfarth

@EBEBRATT-Ed They do have lead lag

RayWohlfarth

@ethicalpaul Not sure about that. You mean like a motorized steam valve isolated each boiler?

retiredguy

@RayWohlfarth, Ditto to what @EBEBRATT-Ed wrote. He must have read my mind and wrote just what I was thinking. By the way, since we service some of the same areas I probably have been in this boiler room.

Mad Dog_2

Ray Ray. I like them all up high off the waterline to get less of a beating and truer readings. In the last few years, I mount all Pressuretrols and Vaporstats higher than typical and the way the come on a package boiler. Keeps the muddy splunck out of the pigtails too! Mad Dog

Mad Dog_2

I usually follow it up with two F & M (Fee & Mason) split ring hangers from the space just under the pressuretrol/Vaporstat over to the nearest immovable object (larger pipe) so no one can knock in to it and push it off kilter. Mad Dog

Mad Dog_2

Like this. I prefer to lock on to black pipe, but secure EMT will suffice. Mad Dog

EBEBRATT-Ed

@Mad Dog_2 I like that idea. The worst was when the MFGs show in their drawings to mount the pressure control down on the #67LWCO. Just dumb IMHO

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1875682#Comment_1875682

yes because otherwise all the boilers would see the same pressure and I couldn’t see the point of the central controls

RayWohlfarth

@retiredguy Im sure you have been there. HB smiths inside.

@Mad Dog_2 I like that great idea

Perhaps this was part of the lead lag system.