irks me

billygoat22

Went on a job this week. Another company installed and the guy called us about problems.
To make a long story short, he thinks the boiler should run longer and the rads heat all the way across.

Complaint was cast iron basebds won't heat enough.
Now the boiler cycles on only 4 minutes or so and off again, on tstat. I tested .4 A, but he's determioned it's .7 because he called support and they said so.

I believe system is oversized for house and shortcycling at milder temps. He thinks the boiler should be bigger, becuase the rads aren't hot all over.
The basebds will heat at about the same rate as rads, but I think they just heat differently from radiators and thats screwing up the temps in house.

Anyone know how these heat compared to rads? Faster or slower?

Steamhead (in transit)

Rads and fin-tube baseboard on the same zone?

now there's a major no-no. The thermal characteristics of these two types of radiation are so different that they're almost impossible to mix. Cast-iron has a higher thermal mass so it holds heat longer, while fin-tube cools almost instantly when the circ shuts off.

If the rads are on one zone and the fin-tube on another, each zone controlled separately, it's not so bad.

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Keith_8

Cold ?

Is the space up to temperature, meaning is the thermastat satisfied?

Assuming the 2 different heat types are not on the same zone and the thermostats are satisfied I would look at the near boiler piping. Is there a bypass between the supply and return? Cold slugs of water may be causing the low limit on the boiler to break power to the circulator.

Give us a little more information.

Keith

billygoat22

Wow, I can't believe I make such an oversight.

It's a one pipe steam system, standing cast iron. It's a two storey house, one tstat. The cast iron baseboards have a two pipe setup, but they could work without traps since the drains are below the water line on the wet returns.

I shut off several rads downstairs and they heated immediately, and he said the rads upstairs are shut off.

The boiler is cycling on the tsat, but the first day when I jumpered the boiler in basement it ran for an 1/2 hour or so and never heated all the rads completely.

He says it cycles faster now than before.(runs about 4 minute and was 40 deg outside) I changed the nozzle to a 1.1 since the boiler was 140 psi and the nameplate called for 1.38 gph. Tha manual called for 1.1 nozzle on the chart, and now he's saying its wrong because somewhere in the manual it states two nozzle selections.

At tstat pulls .4 a for anticipator setting, he wants .7 because the manual says so. So anything you do he's going to be second guessing. It does maintain temp.

I've told him the thing may have ALWAYS had problems (bought the houseabout 2 yr ago)

I'll have to get the pwork to see what rating on boiler was, since I'm not sure the 1.3 pickup was factred into their sizing.

Thanks for the input.

Jamie Hall

Now there's

a homeowner to make you weep... are you sure you need this job? Or is he your brother in law? Or... ?

billygoat22

Seems to be my week for that sort of thing. Three calls this past week for "my heat pump is broke, blows cold air"

Cold = 95 dgrees to some people. Even @ 30 degrees outside and you're getting a 25 delta t is good.

Some of the low end units seem to have a fault in the design. Went going into defrost, it takes 30s or so for sequencer to bring on heat, so they get a short blast of cold air. Not "broke", but differnt control setup would have prevented it.