Anybody have experience with radiant heating?

[hot_pastrami]

Hi guys,

I've been fighting this problem for weeks, so I thought I'd see if anybody here had some experience and/or advice... the house I bought last May is semi-old (1978) and semi-rural. I am slowly recoving the place from it's previous state of ill-repair, but the one thing that I can't get working right is the radiant heating system.

I've had professionals come out twice now, and it's getting too expensive. Since I know nothing about radiant heating, I paid a guy to come clean and service the system when the weather started getting cold. A couple weeks later, it started failing to light most of the time. I replaced the pilot assembly, and that works fine now. Then, one of the section valves and the air bleeder went out, so I had a guy come out again to replace that stuff ($525 later... ouch).

So, all seemed well. But then, it started getting really cold outside, not just chilly. And the radiant heating can't keep up. This morning it was 50 degrees in the bedroom... brr. I have all the thermostats up around 72, and usually by mid-afternoon, a couple of the areas have reached that. But some, like the bedroom, never get above 60 or so.

The boiler seems fine... and in the boiler room if I touch the water lines that lead to the varous areas, they are almost too hot to touch. But if I go touch the wall panels in the rooms, they are mildly warm at best. Not having any experience with radiant heating, I don't know if they are as warm as they should be, but I'm almost positive they should be much warmer than they are.

My best guess is clogged pipes, but if I'm rigt, I have no idea how to resolve that. Another possibility is that the system is fine, but the poor state of the attic insulation is leaking all of our heat out faster than the system can warm things up. I'll call the serviceman again if I must, but I hope to avoid the expense if I can.

Anybody? Thanks.