Can I convert my 2 pipe FHW to Steam? Should I?-

Mark Messina

I have a 15 year old Burnham V-36. The system used to be a steam system (prior to the install of the V-36) and is now a 3 zone FHW. The FHW has many radiators per zone (old cast iron jobs) and has such capacity that whenever heat is called for, the temp in the chamber drops below 140 (sometimes way below if all 3 zones call at once). This is causing condensation and will eventually ruin my boiler. Should I convert this back to steam, and what is required to do this. Also, how does one control the temp now without the FHW system? I know little about steam. Thanks!

kf_2

No to steam

I wouldn't switch back to steam. To inefficient and hard to control. Consider adding a 4-way mixing valve and control with outdoor reset to protect the boiler from low return water temps and modulate the heating system to add comfort.


Hope this helps.
kf

Andy N.

I wouldn't

recommend converting back to steam if you have it running hot water now. I would recommend protecting the boiler with a system bypass at the minimum. this involves a few changes at the near boiler piping. If you want real comfort I would recommend reseting the system using a four way valve or injection mixing. with this arrangement the system (radiation) becomes responsive to outdoor conditions and the boiler is protected from low water temperatures commonly seen in these converted systems. This would also involve some changes to the near boiler piping.


hope this helps.

Andy N.

Mark Messina

hey guys,

thanks for the recommendations. Can you point me to an article or diagram that I can use to obtain a valve and install it?

Thanks,
Mark

John@Reliable

Bypass piping

Check www.burnham.com You will find "heatinghelper" which will show you a set-up for simple bypass

Unknown

It also sounds like

the zones arent controlled by a low limit aquastat ? It will cut out the zones if the temperature falls below the point you set it at - which is usually higher than the condensation temp . We set ours at a minimum of 150 to 160 . Make sure that the circs are controlled by something like that , as well as a bypass to protect the boiler temp , and youll do fine . Good luck .

mp1969

Back to Steam?

Definitely need to keep with the FHW as the reverting back to steam is definitely going backwords. The others were right about a simple bypass of maybe 3/4" diameter from supply to return near thr boiler that can manually be adjusted to keep the differential at most 20 degrees and preferably close to 10 (sometimes hard to do).
All large commercial hotwater systems engineer in auto type valves and piping arrangements to keep the out and in temps within these ranges.I may be dating myself with these temp ranges but I am sure your problem can be fixed with cost effective measures that keep the benefits of staying with the fhw retrofit!
Let us know what works, it is a very interesting question.

MP1969

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Mark Messina

see my new post on speed controls for the pumps please!