replacing a steam boiler

Jamsey

I'm replacing an older steam boiler with a Peerless steam boiler. Since the new boiler is much smaller, looks like I'll need to change the height of the of the return loop where it enters the equalizer at the Hartford loop, to keep the 2" to 4" below the water line. The existing header will be 24" or more above the water line. I'll use swing joints to connect to the header. My supplier tells me that I should use a domestic coil to feed the indirect. Does this sound correct and what else should I be planning to do when installing a new steam boiler. My experience with steam boilers is limited to a few systems I worked on with my father back in the late seventies. Thank you and I appreciate any support you may be able to give. Jim C.

nicholas bonham-carter

Boiler replacement

Double check the edr of your radiators to make sure you get the right size of boiler. Do not choose a boiler based solely on the capacity of the old one, or on the heat-loss of the building.

Make sure the wet return has some provision for flushing out the rusty sediment in the first few months of operation. Put on a good low-pressure gauge (0-3 psi, gauge store.com). A vaporstat and plenty of main (not radiator) venting.

Read the installation manual carefully, and follow the instructions at a minimum, as far as piping sizes, and layout.

If you have more questions, post them on the steam area here for more response--NBC

Steamhead

You don't need a coil for the indirect

the indirect has its own coil. Not sure what Peerless you're using, but it might have tappings for connecting an indirect.



Not all indirects are suitable for use with steamers. Generally the tank-in-tank ones, like the Triangle Tube Smart series, won't work well in this application. But a coil-type like the SuperStor will.



Here's a thread where we installed a SuperStor with a Smith G-8 steamer:



http://www.heatinghelp.com/forum-thread/132567/One-of-the-worst-maintained-oil-fired-boilers-weve-seen

gennady

Water level.

If you had no steam knocking problems, the best way to install new boiler is to mark existing water level, and mount new boiler at the same water level. build bigger concrete pad,

Jean-David Beyer

Just out of curiousity, why not?

"Not all indirects are suitable for use with steamers."



I am not disagreeing. But why not? Is the problem because the water level in some indirects, especially tan-within-tank types is too high and they get dry on top? Or something else.

Steamhead

That's the reason

the top of a tank-in-tank indirect is well above the waterline of a modern steam boiler. But the coil in a SuperStor or similar unit is low enough that it stays filled with water. The SuperStor and the TT Smart indirects' first-hour ratings aren't that far apart, so we wouldn't sacrifice performance by using the SuperStor.

gennady

weil mclain indirect with steam boiler

It is above water level. There is no problem with its operation, 4 families have enough hot water.

kcopp

is there an air....

vent on the Indirect? They come w/ one.. That would have to be plugged shut. No air vents on a hot water loop off a steam boiler. That creates a problem w/ the loop possibly getting air bound. I would tend to agree w/ SH.  You may be able to "get away" w/ that set up but nuisance call backs for not hot water would get old quick....

gennady

Getting away

I just followed manufacturer Installation manual

Charlie from wmass

SInce Weil Mclain no longer uses

tank in tank the newer ones should work. I do not like them due to other issues I have had with them. I suppose it is no different than having a hot water zone above the boiler. I also do not do that with out a heat exchanger. I understand how to do it with out one and I have seen it working several times, I just get called mostly to the times it does not work. The manual for tank in tank heaters requires pressure on both sides last time I read one but I do not remember if it is the outer or inner tank they were more concerned with. I will check and report back.

Jean-David Beyer

Is that because...

... both the supply and return to the indirect in the boiler are sufficiently below the water line of the boiler that no air gets into them? And you filled the boiler at enough pressure that you could purge all the air from the indirect? And you close off the automatic vent at the top of the indirect (or replace it with a manually operated vent that you can close off when done purging)?



And if so, do you need to bleed it once in a while in case dissolved air comes out in the indirect?

Charlie from wmass

This is why I do not use tank in tank with steam

see page 16  http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/water-heaters/indirect-fired-water-heater/indirec_fired_water_heater_plus_indirect_fired_water_heater_manual.pdf

I can not guarantee both tanks are going to remain full of water.

Jean-David Beyer

Yet on page 44

they tell you how to use it with a steam boiler.



The issue of keeping the tanks full is that you want the domestic tank full so the pressure in the outer tank does not collapse the domestic tank. You never have to fill the outer tank (but if you do not, you will not get hot water).

gennady

Inner tank

Collapsing of inner tank is an issue, but lesser in 1.5 psi steam system. Unfortunately in coil tanks this is also an issue, coil tubes are prone to collapsing as well.

Jamsey

steam boiler replacement

I'm using a Peerless WBV04 SPP. The manufacturer rep says using the boiler coil to heat the indirect would work best. I'm using a Super Store. I'm thinking it may be best to raise the new boiler to the correct height, instead of reworking the return on the equalizer piping? any suggestions here? Thank you!

Jamsey

replacing a steam boiler

Thank you for your previous comments.

I'm replacing a steam boiler with a Peerless WBV04 SPP steam boiler. I'm told by the rep to use a coil on the Peerless to zone a Super Store indirect. No extra taping on boiler.

I plan to raise the new boiler to keep the return in the Hartford loop 2" to 4" below the water line. This means I'll need to raise the return into the new boiler. There is a Hoffman dirrerential loop "the watchman of the water line", it and all the piping stays. Can you tell me what this does. Thanks for the input.

Jamie Hall

Ah... a differential loop

I love them.  But they do need to be handled with some care... first, the previous comment on the water line is really critical.  Do raise the new boiler so that the new water line matches the old one within an inch or two.  You'll save yourself a whole lot of heartache.



Second, the purpose of the differential loop is to help get condensate back into the boiler in the event that the boiler pressure rises too much.  They are used on vapour steam systems, and on such systems the maximum pressure is critical.  You WILL need a vaporstat to control the system -- not a pressuretrol -- and you may need to experiment some, but as a place to start try setting the cutout at about 8 ounces and the differential at 7.  You may need to go lower; if the differential loop trips (you'll know) that means you are running at too high a pressure.