Mouat vs. Boiler Feed Pump vs. Reservoir Tank

Steamhead

I've seen that

on a system with zone valves and a boiler-feed pump. There was supposed to be a vacuum breaker there to keep vacuum from pulling water out of the tank and flooding the boiler.

I don't think I could have made that up either.

steve pajek

smaller boilers

Steam boilers must always be sized to the connected load regardless of how much insulation was installed. Insulation has nothing to do with it. This practice can lead to low water problems and high fuel bills with todays modern boilers.

Steam Bunny

> One common mistake is sizing steam based on Low

> Pressure Standards (1 Square Foot Load requires

> 240 BTUH).

>

> A properly functioning Vapor/Vacuum

> Steam system can operate anywhere from 120 BTUH

> per Square Foot to 240.

>

> If you have insulated

> the building and the pipes well you may find the

> system will operate well with a smaller boiler

> PROVIDED the system functions well.

>

> The first

> sign of a misfunctioning vapor-vacuum steam

> system is actually LOSS of heat in some rooms,

> etc.

>

> Jammer Don

Steam Bunny

Steam Bunny

Hello Jammer Don!

I've been pondering a statement by Dan Holohan (see below) and desperately trying to translate what he calls "receiver" into some kind of pump free "condensate receiver". Finally shrugged my shoulders & concluded I had to be reading it wrong. Is it possible you came up with a clever way to get the boiler return trap working again?

If so, that's too bad, as I've not found one on our system- yet.

Re running a system with 120 vs. 240 BTUH/sq'. Could one effect a safer compromize by installing a properly sized system (to address Steve's water concerns) and then proceed to downsize the boiler?

*************

Date: June 29, 2002 09:08 AM Author: Dan Holohan (mailroom@HeatingHelp.com) Subject: I'd be reluctant

to put a feed pump in a house. I think that if the pipes are well insulated and the traps are working and the returns are clear then the return trap can get the job done. If it's working, that is. If it's not, there's another alternative. "Jammer Don" Conyngham of Eastern Penn Supply has his contractors rip the guts out of the receiver and keep the casting. Then he has them install a probe-type low-water cutoff in the receiver. This is wired to a switching relay, which is wired to two small solenoid valves - one in the steam line (normally closed) to the receiver and the other to the equalizing line (normally open) that goes back to the dry return. It works like a charm, and for a lot less money than a feed pump and the extra traps that you need once you add the feed pump.

gerry gill

thats exactly what he did..

and its quite ingenious too..i'll have to remember that if the need arises..you don't have a return trap on your system..mouat didn't use them.

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Steam Bunny

Jammer Don,

you wrote, "A properly functioning Vapor/Vacuum Steam system can operate anywhere from 120 BTUH per Square Foot to 240."

As I've sucessfully run our 1,500,000 btu boiler at 750,000 but/hr for 35 years- confirmed btu needs @ -17 degrees, etc, I wonder if you (or anyone else) might know where I could go for information/explanation/documentation.

Thank you.

Steamhead (in transit)

What he's talking about

is mostly seen today on larger systems with vacuum pumps. But in the days of coal firing with its long cycles, once all the air was out the system could go into vacuum which would lower the steam temperature. So the heat emission per square foot EDR of radiation would be lowered accordingly.

The Mouat was not a "vacuum" system in that sense. It did use a connection from the dry return to the chimney which used the chimney draft to help pull air from the system. This would produce a very shallow vacuum, but there was no provision for holding the vacuum as on other systems.

Your situation sounds like the boiler was oversized. I couldn't find it quickly in the earlier postings: How much radiation (EDR) does the system have, and what is the boiler's rating?