View Full Version : Heater - Does not blow hot air

12-14-2010, 03:36 PM
How are you, hopefully i am posting this in the right place.

I have an Apollo water heater system, when i turned the heat on the other day, the air coming out of the vents is barely warm air. It heats the house, but takes forever and the heater is constantly running.

I did some googling, and some of the things that i read said to change the air filter(done) and to turn the water temp up (done). The water temp is so hot, that when i have to turn hot water on i also have to run cold water just to be able to use without scalding myself. None of it seemed to help, the air coming out the ducts i still barely warm. Does anyone have any suggestions?

My water heater is 50 gallons (same as originally installed)

Checked the temp coming out of the vents and its about 79.8 degrees, according to all the research i did it should be about 95 or so. Not sure what to do...

It looks like the heating unit is made by First Co. out of Dallas Texas and Model number is 30VAq3 3DVAQ3. Any help would be greatly appreciated.

If i need to provide more info, just let me know what you need.

Thank you so much for your help...

12-14-2010, 03:42 PM
Sorry the model number is 30VAQ3 or 3DVAQ3 - hard to tell and the site does not have them listed. Pretty sure its 30VAQ3

12-15-2010, 12:40 PM
First Co builds air handlers- it's probably a custom model for Apollo.

A couple of things might be going on-

1> There may be something restricting flow on the loop between the air hander and the water heater-needs to be verified (or the circulation pump needs to be checked.)

2>The hot water temp may have been inadvertently turned down to 110-115F- fine for hot water use, but maybe too low for a 25F+ delta-T between the air-handler coil and comfortable exit air- cranking it up to 125-130F would fix it (sounds like that ain't it, eh? ;-) )

3>If the air handler has an adjustable aquastat that controls the blower, that somehow got turned down to 90F or something the exit-air temp would start out low and stay low for quite awhile, but should eventually come up to temp if the pump flow and water temp are up to spec.

4> There's enough mouse-nest leaves & dead spiders wedged in the fan coil that it needs to be (carefully) cleaned out, but that might also be detected as a lower air flow.

My bet's on #1- either the circulation pump is starting to fail or you've got something restricting the water flow. (Could be corrosion, or crud, dead salamanders, almost anything.) If there's an easy place to break into it without flooding the house, see if you can't back-flush it with a garden hose to dislodge any crud and test the flow on the water side of the air-handler's coil. See if there's a manufacturer's model name & number on the pump too- they last awhile, but never forever.

12-15-2010, 01:01 PM
Apollo's air-hander manual (http://www.apollohydroheat.com/lit/media/om/om_airhandler.pdf) states that the pump should start up at the same time as the blower. See P21 for some other hints.

A failed dip tube on the water heater might cause this low-temp air symptom as well, but it would almost surely show up during showers & bathing draws too.

12-15-2010, 04:19 PM
Dana Thank you so much for a great write up, and your help.

It's definitely not number two... the water is scalding coming out of the tap. Now it does take about 20-30 seconds for it to turn hot anytime I open a faucet. Not sure if thatís an issue, assumed it was normal.

1. Sounds like this could be an issue, how does one do that? Obviously i need to make sure heat is off on thermostat, and the "red light switch" (not sure of technical terms) is off too. What do i do then? I know i can cut the water coming in and out of the water heater to the air handler. Do i need to cut power? to anything? I've replaced water heater before, never really messed with an air handler.

4. Could also be an issue, i did not use heat since last January, so it was good 11 month before turning it on, not sure if itís an issue... if it is, do you have any instructions (or place where i can get them)?

Also, in googling this problem, i remember reading something about purging lines? I did not do that, not sure what it is or how to do it either :)

In the manual you sent out on page 21, there are other steps... i only tried turning water temp up, insulating pipes and changing filter. Any others worth trying first (maybe they are less intrusive).

Also, i just googled to see what heat traps are (and i have things coming out of the water heater for both warm and cool water). Is this an issue? Should i start replacing those? Not sure if they are heat traps, but sure as heck look like what i see online (and I got the at Home Depot).

Thank you so much for your help.

12-15-2010, 06:26 PM
Are you sure that the circulator pump is actually running? There may be a little convection circulation that might make the water warm, but it needs to be circulating to make the water hot at the air handler so that air can be heated up.

A generic air handler is basically just a fan. It needs something to condition the air, it could be electrical heating strips, an a/c coil or a hydronic coil. If I read you right, you have a hydronic coil...essentially a big radiator in the air handler that the fan then blows over to distribute that heat. That coil gets its heat from the WH and is pumped there by the circulator. If the circulator isn't running, or the impeller is degraded (broken vanes, etc?), then it won't get enough heat there. A circulator often does not have enough head to push water if there is any air in the lines, the pump could be running, but it won't be circulating any water...no water, no heat. So, you need to ensure that the lines from the WH to the air handler are purged of air, and then that the circulator pump is still working properly, and it hasn't burned out.

12-16-2010, 08:37 AM
To be honest with you i am not sure if the circulatory pump is running... how can i check? Same goes to make sure if the vain are broken, water is blocked or air is in the system?

My plan is to spend the whole weekend in the atic (remove heat traps, then do other suggested items/maintenance) so hoping to find out how to check them.

Also, what is this thing purging air out of system i keep hearing about. Can't seemed to find any instructions online on how to do it.

Thank you so much for all the help! Keep it coming! If i can save a buck before xmas by fixing it myself, it would be sweet!

12-16-2010, 01:40 PM
First, find the circulator pump. When the thermostat is calling for heat, take something like a screwdriver, place the blade on the pump and put the handle up to your ear and listen. You should be able to hear the motor humming. You should also be able to feel the pipe coming out of the circulator and notice that it is hot all the way up to the air handler. The return pipe coming out of the air handler should be noticably cooler. If the pipe is not hot out of the circulator, either the pump is not running, or if it is, it can't push the water to the air handler. Check all along those pipes to see if there is a valve you can open to let air out. If you can post a picture or two of your system, someone may be able to point you to places to check.

If the pump is not running, then you either have a bad pump, or a problem with the control circuit.

12-16-2010, 01:56 PM
If the air handler unit is in the attic and the hot water heater is on the first-floor or basement it's possible that it got air-locked. To purge the air you may need to crack a fitting at the highest point in the system (assuming it doesn't have any valves that would let you do this) and let it bleed water out until all hissing & sputtering of air and air-saturated water stops, and let it run some more. (This may take more than one attempt to fully clear it.) Many/most hot-water based heating systems are installed with both a vent and an air-scoop (self-purging device) in line with the pump, and at least a vent at the high point of the system. I suspect most Apollos are installed with the air-handler close to the same level as the water heater, and the top of the water heater is the highest point for the water in the heating loop(?).

12-17-2010, 03:50 PM
Well, tomorrow is D day... i will attack full speed, hopefully come Sunday, i will be:
A. Alive
B. Done
C. With hot air blowing out of the right places :)

Thanks again, i will post updates/questions.