Need expert opinions

Mike T., Swampeast MO

...for such a system. The old boilers keep chugging for decades and the systems will likely live for centuries (barring a nasty freeze-up). Even the unlined brick flues seem to fare reasonably well given the conditions.

The bypass line is supposed to be a "must" on a gravity conversion but I've yet to see one (around here at least). The boilers I see are either converted originals, or 1940s high content or 1970s low content--all simple American cast iron. They keep on going.

I'd be most concerned when it's time to change the boiler. It's likely that the hefty oversizing of the boiler contributes to the longevity/lack of condensation problems. I'd give highest consideration to a high-quality fully-condensing boiler properly sized to the house--either that or simple atmospheric cast iron similarly oversized. The well-documented fuel savings of the former though can very quickly make up for the initial price difference. (40% is known on nearly idential systems with really old high-water content boilers.)

Leon

Here goes :Have hot water boiler with rads heating 2 level house.Boiler is oversized for house.The radiators are oversized for the boiler.Boiler has single circ. with honeywell L8148a aquastat,which cuts on boiler and circ. whenever t-stat calls.My problem is th boiler water temp takes forever to rise before t-stat is satisfied.House is heated fine ,boiler on time is good but it never reaches hi-limit.My worry is the lo water temp,115-120 return and barely ever rises before t-stat is satisfied.What is the best way to correct these lo-temps.I am thinking of adding circ.lo-limit controller (honeywell L6006)which will maintain a higher temp in boiler until t-stat calls.Or should i install abypass line from discharge to return line to keep return temp up.Thanks for any responses.

Eric_3

Don't use the low limit

Use the by pass method. The low limit may cause thermal shock to the boiler when the circulator comes on. It sounds like you have a converted gravity system, someone added the boiler and pump? There should be a skematic in your boiler manual on how they want it piped. If you don't have it you should contact them and get it. hope this helps.

John@Reliable

I Really dislike cold start systems

You could replace 8148 with a 8124 which would control cir. pump plus maintain low limit, I like this in off season to keep boiler warm & dry, as for never reaching hi limit thats ok. Bypass could also help

Joel_3

Or

You could add a 4 way mixing valve with a Tekmar and really improve your comfort level and protect your boiler at the same time!!!!!

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