Help a homeowner (ME)

Unknown

We dont do much air handler work , but the last one we installed we used a Honeywell aquastat set at 130 , makes on the temperature rise , and installed it in a well in the piping - on the return side of the air handler . We dont like those surface mount aquastats much .

It can also be that the diffential of the aquastat is set on a low number - if it can be set at all , because I dont know much about Johnson controls . If it is set at say 5 degrees differential , that would make the fan cycle alot .

[Deleted User]

Homeowner needs help...

I received this e-mail this morning and thought I'd share it with you wallies. I have my ideas as to whats going on, but thought I'd pick your brains before responding. Whaddya think Wallies?


(Begin HO letter)
Thank you so much....

Here goes.. I hope this all makes sense. We just moved in to a house built in 1994. There is an HVAC system with an OIL fueled boiler with 4 zones.
The heating system is Hydronic sending water to 4 air handlers which then blow forced air to vents. During the summer, the AC worked fine. When the temperature dropped and we tried to use the heat, we ran into some trouble.

As I mentioned, there are 4 zones. 2 of the zones have older Enerstat thermostats. These work fine. The other 2 zones have newer Honeywell thermostats and were both problematic. I called in the contractors who installed the system for the original homeowner but I am not happy with the solutions as of yet. As I am learning more about heating systems, I realize that there is something wrong.

The 2 working zones with the older thermostats are wired as if the heating system is Electric. In other words, the fan comes on immediately when the thermostat calls for heat and shuts off immediatly when the desired temperature is reached. Supposedly that is not a "good" way to heat the zone as cold air is initiially circulated until the boiler warms up. As we heat the house most of the dau, this is really not a problem for us.

On the other 2 zones, there is an Aquastat connected to the air handler. The problem is, according to the heating contractor, that there is a "flow control" problem with the boiler. That the valves are stuck open and hot water is migrating up the pipes and not allowing the Aquastat to work properly.

One of these thermostats is also set to the "E" setting for Electrical heat, but this zone seems to work fine. The other zone is more problematic. It is the furthest zone from the furnace and the air handler is in the attic. The
blower seems to go on for 30 seconds and then off for 30 seconds while the zone is being heated. This thermstat was set to the F mode.

I think what is happening is that the flow control valves are probably not working well. To compenstate for this, the working thermostats all are set to the "E" mode so that the air blower comes on right away. This doesnt seem to be a problem because the air is usually warm because of the defective flow valves.

What is the best solution? Thanks much, I hope this isnt too confusing.

Seth

(End of HO's letter)

Let 'er rip Wallies!


I intend to direct the H.O. to this site for answers.

ME



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Gary Fereday

ME, your teacheritus is beginning to show!

Are there Zone valves on this system? Zone valves are electrically controled valves. (flow valves are mechanically operated by the pump & the flow of water.
T/S should call for heat and open up the zone valve. zone valve should turn on the pump. T/S also should enregise a relay that is controled by the water temp (aquastat) leaving the coil it is attached to. Starting the blower when the coil is hot. Or, a time delay relay may be used in lew of the aquastat.
A big improvement would be a differential pressure valve and constant circulation of out door re-set controlled boiler water.
anyway "How did I do Teach?" bigugh

PS--If constant circ is used a approved vent damper should be placed in the flue to stop the draft going up the chimney during off cycles of the boiler.

Seth (HO)

Hi, Im new to this forum and greatly appreciate all the help. I deliver babies by trade and all of this heating stuff is new to me. I am enjoying the learning.

There are 4 separate zones, each with a valve. I am not sure if they are electonic or manual. The biggest problem I am having with the system is as follows: The upstairs zone TS calls for heat. The air handler keeps cycling on and off for 30 second intervals until the TS is satisfied. There is a switch made by Johnson controls that is attached to a hot water pipe going into the air handler. The contractor called it an aquastat. I cannot seem to find a good temperature to set it which will correct this problem.

One of the downstairs zones seems to work better but I still need to keep the Aquastat at about 185 degrees to prevent the air blower from turning on without heat.

Any ideas?

Seth

Gary Fereday

Perhaps

The inoperative aqua stat needs replacement. Set at 185*F should ask the boiler to get at least this hot before turning on the Blower. As for the cycleing, The blower may be running far faster than it should. Drawing off the heat the coil makes so fast the aqua shuts it down. A Smaller & or a more open drive pulley may well adjust the blower speed to a more equitable speed, running longer, and hotter.
An outlet temp for the air comng into the room from the coil should be comfortable, usually about + - 135*F. To fast a air flow will lower this. cool the coil faster than it can handle, shut off the blower and reset very quickly. Another thing that needs to be addressed is if the system is full of water and not air bound. There should be some way to vent all the air at the coils. anyway bigugh aka Gary Fereday

Gary Fereday

If the blower

motors are direct drive, (no pulleys & or belts)so as to furnish summerA/C I'd bet they do not slow down for winter heat. That is accomplished by electrical relays. High air flow is needed to cool and slow air flow is needed to heat. this is usually accomplished by the switching between summer and heating on the T/S. At his point a good technician is needed. anyway bigugh

Seth (HO)

Thanks. The air handlers in this case are Lennox CB19's which are also used for the AC. Im not sure that there are separate fan speeds. It also appears that the aquastat is wired in such a way that the TS cannot turn on the fan independantly. I would just as soon remove the Aquastat and turn on and off with the TS. I guess that would require some re-wiring at the level of the air handler. It sounds like Im in deeper than I thought and should get a technician in.

Gary Fereday

Now your

getting the Idea. Look at "find a Contrctor" on this wall and see what comes up. I am in utah, and not able. I wish I were near you. We could have a time. but to late to trade work. I got ten kids, all adults now and 35 grandkids, that seems to be it for deliveries for me. oh well!

Seth (HO)

Thanks again. Its just strange that the two zones with the older type of TS work fine. Makes me think I should just replace the 2 TS in the non working zones.

Seth

Alan(CaliforniaRadiant)Forbes

I was all set

to deliver my own children, but my wife calmly told me to hire a professional. I pulled out my journeyman's card (with photo) and told her that I had plenty of experience and work with pipes daily. "No way" she said; "you'll botch it up just like all those plumbing jobs that I hear about".

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Seth (HO)

Pictures of the system

Here are some pictures of the system. I hope they help explain some of this.

Seth

Unknown

Looks like my co. services the boiler

I work for Meenan Oil in the installation department on Long Island . It looks like you have a semi - commercial Weil Mclain 78 series boiler ? How big is the house ?

Mike Kraft

Seth

Agreed with Ron Jr and Uncle Big UGh(i'm still scratching my head in referance to surfn' dudes response )anyway...........sounds like the aquastat (strap on) is set to high.That is your on off switch for the fan.If the water cools below 185* shes cutting off.try 135*-140*.You may need a new aquastat as suggested.

cheese

Seth (HO)

Yes, I agree the Aquastat is set too high. But thats because the fan tends to run way to long after the TS shuts off. My heating contractor said its because the pipes stay too hot because the flow valves are stuck open. Rob, you are right. I just signed a contract with Meenan. They have been great so far. Do I need to have someone come in? Does Meenen service the Aquastats as well as the boiler?

Unknown

I think you can get

different contracts on service . Some cover one zone , and some cover all of them . We have some sharp troubleshooters in the service department. If you call the main office at 516-783-1000 and ask for Tom Hewitt , the service manager , he can tell you whats covered and send someone to take a look . Good luck and take care , Ron .

Chauncey

Is there sufficient pressure to get water into the

coil in the attic? C

Frank_17

aquqstat

the aquastat should have a heat trap to keep the pipe cold until a call for heat. Just llop the pipe down 12 " ( make an "S" in the pipe . keeps unwant heat from migrating. 180 is way too hot

ScottMP

Seth

we just finished a hydro-air job. We installed a Taco relay, I believe its a C201. This is a time delayed relay that use's a time delay to operate the fan instead of a aquastate. The fan do'snt come untill after a preset time period, allowing the temp to come up, it also shuts off sooner which eliminates the differentail in the aquastat running the fan even though the temp has dropped.

I think this would eliminate your problem. I see nothing on your boiler that would cause problems, allthough all of us here would pipe it differently now, it still should work.

My suggesttion would be change all thermostates and relays just to be safe and cover all bases.

Good Luck

Scott

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Seth (HO)

More details

Maybe this will help diagnose the problem. I lowered the Aquastat pictured to 140. The blower clicked on seconds after the TS called for heat. When the room tempearture reached the desired temp, the blower stayed on for quite a while afterwards. I think a time delay system would be much better but I have no idea how to install that.

I am also curious as to why most of you would pipe the system differently now. Is it worth having it "re-fitted"?

Thanks

don_9

I think a flow check on each return would be a good thing.
Would also add a disc type fan switch as close to the outlet of the coil as possible.Most fan switch/ aquastat should be set with a 20 degree diff when working fans.

No disrespect, but you have a contact with ron jr and crew
why not make the call in let them do what they do best.

Unknown

If I am not mistaken

Once the thermostat is satisfied , the blower should shut down immediately . Sounds like your blower is wired in directly with the aquastat ? It would be better to have the blower turn off when the zone turns off . If the heating thermostat wires go into the air handler , then adding a simple relay would do the trick .

Piping the boiler differently would include moving the circulators to the supply of the boiler and letting them pump away from the expansion tank - it would make the boiler more trouble free with getting rid of air , if you had a problem with it .

Seth (HO)

Ron you are exactly right about the wiring. The blower motor is controlled only by the aquastat. Not by the TS. I think it should be controlled by both. I spoke to Tom at Meenan today and he is sending someone in the morning. Thaks so much for the help. I will keep you all advised.

Seth

J.C.A.

Another ...

Satisfied customer ! Ron Jr . , great call ! P.S. Maybe you should get some kind of kickback for getting the "New Customer" . Seth , sounds like your in good hands . Best of luck . Chris .

Seth (HO)

SOLVED!

Thanks to all of you and especially Ron Jr., the problem was solved today. The staff at Meenan here on Long Island is exceptional. The problem was with the location of the Aquastats. They were attached to the pipes going INTO the air blower rather than the pipes leading away. Thats why it took so long to shut off and why I had to set it to an extremely high temperature. Right now everything is working great! Its been a pleasure troubleshooting this with all of you and again, thank you for all the help. If I can return the favor in any way please give me a hollar.

Seth

Unknown

Its our pleasure

Hearing that the problem is solved , and helping out in a small way online is a good feeling . Dans website is great . Thanks for choosing us as your heating company , Seth .

Unknown

Just watch Chris

With digital cameras and camcorders getting cheaper by the month - pretty soon servicemen are going to do alot of their work behind a computer - guiding the customer as the tech watches online . Thank you Chris .

Mark Eatherton1

Hey Doc...

Glad you got it resolved. Ron Jr.s a good man. Here's what I was going to recommend as an overall fix.

First off, I'd move the circulators so that they are pumping away from the boiler and the expansion tank connection. I'd also consider the possible need for gravity flow control valves on the supplies and the returns. The higher the system piping, the greater the need to keep gravity in check. I'd also add a centrally located air scoop/ air seperator with an automatic air vent on the piping between the boiler and the relocated pumps.

I'd also flip the expansion tank so that it's tapping is on top of the tank. In fact, if you add an air scoop/seperator as explained in previous paragraph, you'll have a good place to hang the tank in the correct position.

I'd modify the control logic as follows. On a call for heat from the thermostat, a triple pole single throw, normally open relay would be triggered by the thermostats call for heat. One pole would "enable" the blower motor through the strap on aquastat. One pole would start the corelating circulator, and the last pole would turn on the boiler.

Sequence of operation is as follows; T-stat energizes 3 pole relay. Starts circulator and fires boiler. Aquastat is open until hot water has made it through the coil. Once hot water is confirmed via the aquastat, blower motor is turned on. Blower, pump and boiler continue to run until thermostat is satisfied. Upon cessation of call for heat, pump, boiler and fan are turned off regardless of wether or not residual heat is still available. It's going to end up getting into the house anyway.

Anyway, That's my take on it Doc. Thanks to everyone for their valuable input on this thread. We all learned something, and the HO ended up getting his problem resolved.

Congrats to everyone.


PS Doc, I'm beyond child rearing age, but have three daughters that can bear children. Who knows, I just may be dropping you a line some day asking for your advice.

Ain't the internet something!!

ME

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