adding radiators to existing system

sarah_4

I want to add a couple of hot water radiators to an unheated area of my 150 year old house and want to be sure my plan is logical.

The boiler is a not-so-old utica, but the radiators are ancient Gurneys, sized for the old days when people slept with the windows open. Am I correct in thinking that the following are the steps I need to take?

1. do a heat loss study
2. size the old gurneys
3. see if, by making a couple of the gurneys smaller, I will have enough gross output from the boiler to add new radiators without getting a larger boiler?

Any input would be appreciated. I am an experienced plumber, but have limited experience in heating.

Thanks.

Sarah

ed wallace

adding radiators

welcome sarah you are doing the right things such as a heat loss

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Steamhead

Sarah, you're on the right track

I'd do a heat-loss on every room in the house and compare it to the radiation that's there. From this you will be able to establish the water temperature needed to heat the house.

The original design probably used 180 degrees at the boiler and a 20-degree delta-T, which translates to an average temp of 170 degrees in the radiators. This was when the house probably didn't have any insulation, storm windows, weatherstripping etc. So if you've added any of these, the existing radiators will not need 170-degree water to do their job. You may find they need water at 150 degrees or less, as I did.

Size your new radiators to match the existing system water temperature, and your system will heat every room in the house evenly. And with the lowered water temperatures you may find, you may be able to take advantage of condensing technology when it's time to replace the boiler.

Oh, and if you're tyiing the new radiators in at the boiler, now would be a good time to switch to "Pumping Away". This will give you a better, quieter system.

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