Sluggish Water Temps

This year I've notice my system has been really slow to respond when there is a lot of demand for heat, when 2 or more zones call for heat at the same time, as they do first thing in the morning when the thermostats automatically jump up 2 degrees. This morning in particular it was very slow to respond, the house was pretty chilly, and my water temp dipped down to 110 degrees. I've never seen it that low unless the fire was completely out. Surprisingly, I had plenty of fire in the firebox, it looked really healthy and was putting off a decent amount of heat, it just seemed like it wasn't being transferred to the water very efficiently. The basement zone has 2 large cast iron radiators, and that zone was calling for heat at the same time as the other two, so possibly it's as simple as staggering the thermostats so its not trying to bring up the entire house at the same time.

I haven't had this issue in previous years, on the contrary, my basement is my dump zone, and would pretty much always keep the radiators warm just dumping alone. This year though, I tried to address that by making some adjustments to the barometric damper. After taking it off and cleaning and adjusting it, I discovered it was set up completely backwards, set for a vertical installation, while I have it installed horizontally. I'm thinking that worked a little too well and I might just have to experiment and get it dialed in better.

I had some ash built up in the heat exchanger which I cleaned out this morning, but I know I've definitely seen it worse.

My question is, are there any other things to check if I have plenty of fire, but the water just isn't heating up as quickly as it usually is?

You don't mention your device's brand name so I'll take a shot it has a squirrel cage combustion draft blower. If so, clean the blower blades with a tooth brush. They tend to pick up hair and dust which can reduce its ability to move air by a massive amount. If not, check the stovepipe for ash accumulation. That's all I've got until there's more info.

Van Wert Simplex Multitherm

In his profile.

Well, that proves it Lee----when your not drinkin---you're thinkin!!!!!!!!!!!!!!!!!!!!!!!!!! LOL

Same thing happens when my radiant slab hasn't run all on a sunny day and the concrete gets cold. Then in the evening the first time that 1020sqft slab calls for heat its such a surge of cold water the boiler drops down to like 140 and takes a little while to recover. I feel its normal as everything coal is slow. Slow to ramp up the bed and slow heating 40gallons of water 40 degrees.
I now have a tekmar thermostat with sensor that keeps slab at 65.

Staggering those thermostats would help, and so would throttling the flow of water to those zones.

It is also possible your coal is different and not as responsive.

So, circ. pump are working 100%???

Another thought is, maybe air pocket blocking...or air pocket in pump...do some air bleeding.

A BIG plus 1---sometimes the obvious escapes us???

If you have the automatic vent valves to purge air , you might want to check them. Check your feeder valve along with the backflow preventer. Check your expansion valve and check valve. Check these after you purge your system. Good luck.

When you say you adjusted your barometric damper;
are you telling us that the damper door weight is not
pushed all the way to the right and locked in place
which is what the folks at Field Controls want to see
on a coal boiler?

Couldn't have been too serious, he hasn't been back since he made the OP.

I realize this was 2 years ago, but for posterity, I cleaned out my heat exchanger area and set up the baro damper for a coal boiler, and things have been working ok. I think that one morning was just a perfect storm where the outdoor temps dropped quickly and my 2 basement radiators were ice cold when the thermostats started calling for heat.