steam boiler

Paul S_3

I have this steam boiler replacement coming up in about a month. existing boiler has a steam leak in 3 sections. existing boiler is 900,000 btus. I will be returning to measure all EDR in building to size new system. system is a one pipe gravity return, with all wet returns. I would like to do a 2 boiler setup, I myself have never done this arrangement I have seen JSTAR do this and recently EZZY T. I will be doing a 6 inch header. and using a TEKMAR 279 ( or should I use a HEATIMER??). my question is on how the piping should be... do I pipe individual headers into the main 6 inch one with individual equalizers and Hartford loops??? or to I pipe it with one header for both boilers one equalizer one Hartford loop??....and how can I control these should I stage them? or use one big boiler? thanks Paul S

EzzyT

Paul I've done both set ups, it all comes down to how much room you have to work with and if you have the room I would go with more then 2 boilers of course once after you've figured the EDR.
I know out here in NJ Tekmar are more readily available even though Heat-timer is located Fairfield NJ. Stage firing would be done with the pressuretrols that come with boiler as hi-fire and vaporstats as low-fire. So lets say you have 2 boilers set up and call for heat happens both boilers fire and as the pressure starts to build in the system say for example 4oz then one of the boilers would shut down and the other would stay on to maintain pressure in the system. You wouldn't match the boilers to the EDR though, if your going with 2 boiler set up you have each one of them sized to 60% of the EDR, plus you get redundancy.

Paul S_3

would I use just one vaporstat?could you please go in more detail I'm not getting it.... and how should it be piped? I see on your install it looks like its one 6 inch header one equalizer and one Hartford loop... and the return for the boilers seem to seem to run into the first one then it tees off and runs behind the boiler to the other one thanks Paul S

EzzyT

Yes you could or you can pipe a manifold right off of the header creating your own pigtail/trap water seal with the a dual manual reset pressuretrol, pressuretrol and vaporstat those would be additional with ones that come with the boilers

Paul S_3

i understand all of that im just not getting the circuit exactly so I'm staging the boilers with the R, B & W terminals on the vaporstat

nicholas bonham-carter

Only one vaporstat is needed, but with the poor opinion most of us have of Honeywell pressure controls, it might be good to have 2, so the second one can be used as an emergency replacement for the main one.
If you size the boilers right, one firing boiler will not ever get up to such a high pressure as to trip the vaporstat.
Adequate main venting, and slower rad venting will be the key here, (Hoffman 40's).
Maybe trying a good thermostat (Honeywell Visionpro, with remote sensor) first would be a plan, before going with the Tekmar. The thermostat will be more understandable to the customer, whereas any amateur fiddling with the settings of the Tekmar will result in unpaid call backs for you!
There is always the EcoSteam designed by one of our contributors here which is more up to date than the others.--NBC

Paul S_3

ok so to make sure I will use 2 vaporstats one for each boiler.... for example on a call for heat both boilers will fire, boiler # 1 has a vaporstat setting between 4 & 8 ozs ,boiler # 2 vaporstat setting is between 6 & 10 oz... once system pressure reaches 8 0zs boiler #1 will cut out, leaving boiler # 2 still running...if its really cold and boiler # 2 cannot handle load system pressure will drop turning boiler # 1 back on....LOL do I have this right?? Thanks Paul S

EzzyT

Yes exactly just like that, also along with a switching relay

SWEI

nicholas bonham-carter said:

with the poor opinion most of us have of Honeywell pressure controls, it might be good to have 2

I would give serious consideration to a Dwyer Photohelic (or two) as the operating control, sensing pressure off the header or drum. A Pressuretrol (manual reset ideally) on each boiler will act as a safety limit.

EzzyT

Yes esspectially how poorly and inaccurate the new vaporstats have been.

EzzyT

@MarkS set up that he posted on the forum about a month ago came out to be a lot cheaper and more accurate then the vaporstat set up

nicholas bonham-carter

Forget the tenants-I would worry about the owners!--NBC

Dave0176

Paul you could use two Weil McLain 580s.

SWEI

Why not install 279 in a locked office or closet?

SeanBeans

where is the boiler your changing out?