Cold House/Hot Air not Blowing


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Old 01-03-14, 11:27 AM
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Cold House/Hot Air not Blowing

Brand new homeowner...just moved in two weeks ago and I have a bunch of questions regarding the heat that I hope someone can help me with.

It doesn't feel like the hot air blower is blowing warm enough. It's luke warm and takes forever to heat up the house/rooms.

First off the house.

Built in 1923 - Plaster interior and stucco exterior (recently bricked front). Not sure if the walls were ever insulated (my uncles house is in the same area, same style and built a few years earlier and he said his weren't. This could be part of the problem I'm sure)

It has 6 zone heating (5 radiant floor heat thermostats and 1 hot air thermostat)

The previous owner was a plumber and did some high end upgrades which adds to my confusion/lack of knowledge of the work he did.)

Tekmar 374 Bolier Control
Weil Mclain Gold Plus Water Tank
Weil Mclain Hot water heater
7 Circulator Taco Cartridges
Lux Pro Thermostats for all heating Zones

I left the factory presets for all of the settings in the Tekmar 374 Boiler Control but figure these can be changed for optimal heat. These are the settings while the heat was on

Mix 1 Sup 135 degrees / Room 75 degrees
Mix 2 Sup 126 degrees / Room 70 degrees / Boiler Room 70
Boiler 196 degrees
Outdoor temp 10 degrees

I have attached pictures but I'm sure you will need additional info to help. Please ask any questions and I'll try and find the answers for you.

Once again I am a New Homeowner w little to no experience with any of these things. The extent of my experience was my dads/moms house that had a standard boiler with baseboard heating.
 
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Old 01-03-14, 11:56 AM
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Sounds like a fabulous system

It sounds like you see the problem to be that the forced air system doesn't heat up the rooms fast enough. But the system is designed so that most of the heat is provided by the hot water radiant floor loops. The hot air just provides a little supplemental heat to speed up the air temperature response to changes in the thermostat settings.

Forced hot water loops typically take much longer to react to a change in the thermostat setting than forced hot air, but they provide a steady room temp when they reach the set point.

For example, if the thermostat settings for the radiant systems are set lower than the hot air setting, then you are basically trying to heat the house with the hot air system only, which would not be able to hold the temp.

What were the thermostat settings for the room temperatures that you quoted in your post?
 
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Old 01-03-14, 12:08 PM
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Thanks for the quick reply bentlerf. The hot air blower temp is set for 65 and the radiant to 65 or 70 depending on the room. I also forgot to say the radiant heat is only for the main living floor (living room, kitchen, foyer, dining room and bathroom). The upstairs is only heated by the hot air.

So from what you stated I should keep the temp for the radiant floor heat higher (70 or 75?) compared to the hot air temp (65?). I should also mention the hot air thermostat is upstairs so if it gets colder up there (and it always does) the blower kicks on.

Should I keep the floor temp constant through out the day so it doesn't turn off and take a while to heat back up? Will that save on energy costs since it will take longer to heat up the floor once it cools down? Sorry for all the questions but like I said I'm new to all of this. I appreciate all of your help
 
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Old 01-03-14, 12:27 PM
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Ah ha. The information about the separation of the zones helps. I assumed that the forced hot air operated in the same zones as the radiant loops.

So to take your issues in order: the heat from the main living floor will reduce the load on forced air system upstairs. If you find your hot air system upstairs is not able to reach the temperature you would like, it will certainly help to raise the settings downstairs a few degrees.

Having said that, I wouldn't worry too much about lowering the main living floor settings at night, so long as the upstairs remains comfortable. It is true that radiant loops take a few minutes to respond, but that can be handled by raising the thermostat settings a few minutes ahead of your wake up time. You will definitely save money by lowering temps at night, even though it takes a few minutes longer to get back up to comfort range.

Moving air always feels cooler than static air. If you are concerned that your hot air system is not performing up to specs you should measure air temps at the supply grills and the return grill and post them, along with some information on the coil temp and blower type. I am not a professional but I bet one of the professionals on the board will quickly tell you if there seems to be a problem. And make sure your air filter is not clogged.
 
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Old 01-03-14, 03:01 PM
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Thanks again bentlerf. We just had the HVAC ducts/systems cleaned and serviced. Apparently between the work we did on the house and the dust/cat hair from the previous owner, the filter was clogged pretty bad so I think I'm good on that front.

The part about the moving air makes sense so I'm going to measure the air temps by the ducts to see what it is. I'll also post the blower type but how would I get the coil temp?
 
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Old 01-03-14, 06:34 PM
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One of your taco pumps is circulating water through the heating coil for the upstairs zone. The pipes will be insulated, but you may be able to find an exposed fitting at the coil input/output where you can put a temp gage in contact. If not, make a hole in the insulation and take a reading (assuming you have something that will measure temperatures up to 200 deg F). Input temp should be close to your boiler temp (if things are working ok). Output temp will determine how much heat is being transferred to the hot air flow.

Input and output temps would be useful. Duct size, coil size and blower model/specs would be nice, as well as the gpm spec on the taco pump for that zone. All this will help determine the BTU capacity of the forced air subsystem, and whether it is operating properly. Whether that BTU capacity is adequate to heat your upstairs zone is another question. But at least it will identify if there is a problem with the operation.

Now that I understand that the upstairs zone is operating separately, could you just confirm the upstairs thermostat setting and the upstairs temperature? You said it was "cold" but the two temperatures you quoted were both above the thermostat setting of 65 degrees that you mentioned. The question is going to come down to one of how many BTU per hour you need to keep your upstairs zone at the temperature you would like.
 
 

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