Maximum efficiency for old boiler

Andrew N, Milwaukee

I have a hot water system powered by a 1930's vintage boiler made by National Radiator Company which was converted to gas in the 50's along with a circulator and flow control valve. How can I maximize the efficiency? I was thinking of opening he flow control valve. I have also heard about leaving the circulator running constantly and having just the burner controlled by the thermostat instead of them both coming on at the same time. Does a flue damper save much energy?

Andrew N, Milwaukee

Maximum efficiency for very old boiler

I have a hot water system powered by a 1930's vintage boiler made by National Radiator Company which was converted to gas in the 50's along with a circulator and flow control valve. How can I maximize the efficiency? I was thinking of opening he flow control valve. I have also heard about leaving the circulator running constantly and having just the burner controlled by the thermostat instead of them both coming on at the same time. Does a flue damper save much energy?

Andrew N, Milwaukee

Maximum efficiency for very old boiler

I have a hot water system powered by a 1930's vintage boiler made by National Radiator Company which was converted to gas in the 50's along with a circulator and flow control valve. How can I maximize the efficiency? I was thinking of opening he flow control valve. I have also heard about leaving the circulator running constantly and having just the burner controlled by the thermostat instead of them both coming on at the same time. Does a flue damper save much energy?

[Deleted User]

If it were me...

I'd RIP IT OUT, and replace it with a modulating/condensing boiler.

The fire box on that fire breathing dragon was initially intentiionally oversized to allow the Jones to only have to stoke it with coal twice a day. When it was converted to gas, the people who did that were guessing at the energy needs of the dwelling, and the last thing they wanted to do was undersize it.

With some older larger water way boielrs, it is possible to OVER pump the boiler, causing it to actualy perform worse.

Getting rid of it will problaby reduce your gas bills by around 40 to 50%.

And that's probably not what you wanted to hear (rip it out), but that IS the right thing to do.

ME

Steamhead (in transit)

I agree- replace it if you can

newer boilers, mod-con or not, will give you much better efficiency than you now get. Even a well-done conversion cannot equal a new boiler's efficiency. BTW, if the circulator and flo-check are really old, the boiler may have been oil-fired originally.

With a house that old, however, one may not be able to install a mod-con so that it meets Code. This type of boiler cannot be exhausted up the chimney, so an alternate location is needed. The exhaust point has to be well above the snow line and far enough away from windows, doors etc. This is a safety issue.

If you can't use a mod-con, the next best thing is a wet-base boiler (as used for oil) with a power gas burner in it. Not all manufacturers offer this option from the factory, but it will be roughly 6% more efficient than the usual atmospheric type of boiler.

Here's a pic of one we installed- a Solaia with a HeatWise gas burner. This combination is available from the Solaia factory and was not field-engineered.

Does your current boiler have an old tankless coil that was used to heat your hot faucet water? If so, and the coil is no longer used, does the burner still keep the boiler hot all the time?

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Brad White_184

No where to go but up...

You are getting advice from two who know well. You cannot polish a sneaker and call it a dress shoe.

Depending on the fuel you have available, you have options. I would get hopping on planning a replacement done intelligently and reap the benefits.

If your house has been insulated since the place was built, your radiators will be blissfully over-sized, allowing the use of lower water temperatures. If your house has NOT been much improved, I would do that first and the final best result would be used to size the boiler.

A gas-fired ModCon is a great match for over-sized radiators in a house with an improved envelope. If you have oil, there is still much benefit.

Size the new boiler to an accurate house heat loss and go forward. Stick around here and ask questions; you will be well-served.

Andrew N, Milwaukee

I agree- replace it if you can

It does have the tankless coil for hot tap water, however it is disconnected. My boiler currently operates with the burner and circulator coming on at the same time when the thermostat calls for heat, which I'm not sure is ideal. The water temp varies by how often the boiler comes on. I'm not sure how big of an ordeal it is to replace these things - It may be full of asbestos and probably would have to come out piece by piece with a sledghammer, from what I've heard.