steam heat system flood again and again and again!

tom_82 · December 2006

Hi,
We have had several(6) system floods in the past month and a half.
The first time happened the same day we had a main pipe split.
THen it happened a couple of days later. We have a m&M 150 pump controller and a boiler feed pump on the reserve tank. The technician said to have the M&M 150 controller serviced.

We ended up having the whole assembly replaced (float and switch)

The pump stuck again and the system flooded.

Then the switch was replaced with a mercury switch. (we are in Massachusetts)

All was good until last night. The system flooded again.

After the countless gallons of water were removed from the system. We turned it back on and watched as the water surged and tripped the controller and consequently the pump.

So, why would the switch stick (or the pump stick)?
the pump is 6.4 amps, there is no relay between the controller and the pump.

THanks
TOm

The pump stuck again

Ken_40 · December 2006

The M/M 150 ...

is among the most bulletproof controls on bigger boilers and is probably NOT the culprit.

The 150 is only as good as the piping and pressuretrols on the boiler. If you run more than 2 p.s.i. of steam, that may be one problem. If the M/M is piped properly, the cross tees must be pulled and the upper and lower pipe connections (assuming they are not influenced by improper points of boiler fittings/connections) MUST be cleaned and inspected annually.

If the boiler watr is treated, I'b bet lunch there's too much of it (the treatment)present - causing priming and surging, which will cause flooding like mad.

Make and size of boiler? Got a digital camera?

Hopefully, there's a known to be good check between the feed pump and resevoir?

Finally, when was the last time anyone checked the boiler water for TDS? You blow down how often?

tom_82 · December 2006

Let's see.
We blow down the boiler once a week. THis was not always the case.
what's TDS?
What is a known to be good check?

I will run home at lunch and get a couple of digital images.

The boiler has low and high heat pressuretrols. High heat (i will double chck) has cut in at 2 and cut out at 4#. The low heat has cut in at !.5 and cut out at 2#. (again will check)

TOm

Unknown · December 2006

If it was stable before,

It might be dirty, oily water from the new piping work.

Noel

tom_82 · December 2006

Thanks Noel.
the water is and seems to have been always dirty, dark brown... The only new piping is the the new 150.
I'm running home now to take some pics.
TOm

tom_82 · December 2006

tom_82 · December 2006

here are some pics.
sorry i didn't write down the size.
So, obviously this is costing us some money. I am worried about lots of things in this system. And we can hopefully adress these with a qualified pro. I have posted and received some great information in the past and I thank you all.

I really don't understand why the switch would stick???

Should there be a relay between the control and the pump?

also, I was reading about bull head t's. is that one ?

Thanks for your help.
TOm

tom_82 · December 2006

What about skimming the boiler water or treating it chemically?

Unknown · December 2006

skimming is where I'd start

tom_82 · December 2006

Thanks Noel,
We are gonna have a tech out today to skim.
I read in some of Dan's material that cold skimming from a horizontal tapping is best, and should be done slowly. Does the boiler have to be cold to do this...kinda like the fat in soup ends up on the surface when it's cold...
Thanks
TOm

Unknown · December 2006

cold enough to have a smooth water surface (not boiling)

but as hot as possible, to thin the oil and move the oil more easily. Many boiler manuals briefly describe it, and what port to use.

Check the pictures on this page...

http://www.slantfin.com/spec-galaxygxh.html

Noel

Mark Hunt · December 2006

Put

a relay in.

Watched this exact thing happen a few years ago. The relay fixed it.

Mark H

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tom_82 · December 2006

I might not be the sharpest knife in the drawer.
When I got home, it ocurred to me what you said earlier. We DID re-pipe the busted main...duh...and that was the first time the boiler flooded...

At any rate, a tech came out this afternoon but I didn't get home in time to see what he did. I don't think he skimmed the water it says he flushed it on the tag. I'll know more tomorrow. THe water was perfectly clear when i checked it. I'll go down when it comes on and see if there is any surging.

Would the switch on the 150 stick if it is triggered too many times? every time the system flooded, it flooded hunreds of gallons into the pipes... I still don't understand how that would happen.
ANyway, I appreciate your comments. and thanks for the link.
TOm

DanHolohan · December 2006

M&M

sets the switch in the 150 while it's under high pressure (they use air for this). That compresses the bellows and lengthens the stroke distance between pump off/pump on/cutoff. When you use that control on a low-pressure system the bellows extends and shortens the stroke and makes it much more senstitive to a surging waterline. Because of this, they make a 150-MD control. The MD stands for "Maximum Differential" and the only difference is that they set this control while there is low pressure inside the device. You can change just the head of the contol to get the MD feature. Hope that helps.

tim smith · December 2006

overfilling steam boiler

What about this maybe, I find some times on steamers that during the off cycle as it cools, it goes into a vacuum and pulls water through from the feed tank. I notice a lift check on there but that won't stop this so we use a line voltage solenoid valve in series w/ pump power on discharge of pump to prevent this. ? just a thought, Tim

tom_82 · December 2006

Thanks Dan,
I think I read that in the "lost art" book.
I will mention it to our technician.

I'll see you in Sommerville!
TOm

tom_82 · December 2006

Thanks TIm
We can here the pump go on and stay on. We have to manually free the switch on the 150.
TOm

Mark Hunt · December 2006

I really think

you need to add an isolation relay.

I have seen this happen before.

Mark H

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tom_82 · December 2006

Mark,I don't know much, but it seems that if the pump is staying on...we need something between it and the controller to prevent it from sticking...
I understannd the surging will cause the pump to go on, and we need to adress that, BUT we need to also prevent the pump from sticking on. I think I agree with you.
Besides,when I first found out the system flooded after a new 150 was put it, I contacted a rep from M&M. He said you need a relay on the new 150's(with snap switches) if your pump draws 7.4amps or over. Ours is 6.4. He said to put one in anyway.
If I contact an electrician, will he know what to put in. Or should I contact the heating contractor?
Thanks for your input Mark.
Tom

Mark Hunt · December 2006

I'd start with

an electrician. All you need is an isolation relay with a normally open set of contacts and a 110v coil.

I had a system do the exact same thing to me a few years ago when MM stopped using the mercury switches.

The "feed" contacts on the 150 will energize the coil in the relay causing it to close the N.O contact. You will have to bring power to one side of the contact from a source other than the 150. The pump will then turn on when the contact closes and turn off when the contact opens.

Not sure why MM does not use a different switch in the 150. They have known about this from day one.

Best of luck, I think your problem is soon to be a thing of the past.

Mark H

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tom_82 · December 2006

Mark,
Thanks again.

TOm

steam heat system flood again and again and again!

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