Voltage too High?

Rudy

Six mo. old closet install in finished bsmt. New construction work done through developer/GC. Relays and boiler (atmospheric w/ vent damper) are noisy on zone or limit startup.

Checked voltage...128VAC primary, 29VAC secondary. Is this high enough to make the boiler relay AND cubes sound like a screen door slamming? The GV and damper are unusually loud also. I need manufacturers backup on this one but I'm counting on your wealth of experience for moral support.


Thanks, Tom

S Davis

Relay

If your relay is a honeywell transformer/relay combo they are prety noisey when the contacts close, as for voltage being to high I really don't know.

S Davis

Rudy

Can I use a rheostat...

to check my theory? GC wants me to change the relay (yes its Honeywell DPDT in boiler control cabinet) and zone panel to keep the HO happy. I would gladly oblige but I don't think it will solve the problem. I've had a wall full of HW 832A's that were quieter. I thought utility co. voltage should be 120V plus or minus 5%. Could I TEMPORARILY wire in a rheostat or some other device to throttle primary voltage and see if things quiet down before I start changing out otherwise functioning controls? Will a fan speed control or hi-watt dimmer suffice? If it works what's a permanent solution? A resister wired off the 24V side? Sounds like a warrantee voider to me.

This is new construction with new electric sevice transformer. I don't want to get in a p#*%#ing match with the GC, electrical contractor,AND utility co. Of course the object is to keep the customer satisfied. The mechanical room (boiler and forced air system) is adjacent to the guest bedroom and they say all that clicking wakes their guests. What a wacky problem!

BTW, when I mentioned the possible high voltage (128V throughout house) scenario to HO she said she's burned out two irons and a coffee pot since moving in.I'm not trying to pass the buck, just make everyone happy and move on. Any advice would be appreciated.

TG

flange

128 on the line side should be okay, but 29 on the low voltage side is too much. is the transformer tapped correctly? most manufacturers will tell you anything over either 26 or 27 volts on the low voltage is too much.

Dave_8

Voltage

I am not seeing a real voltage problem at this point, just one question. What are you useing to check that voltage. A "true" rms meter will quite often show you 27 to 29 volts on the the control circuit.

Don Baker

As an electrician... we don't get alarmed until the voltage exceeds 10%. Your incoming sound a little high but fine, the low voltage transformer is suspect in your case as it is close to exceeding that 10%.

bake

Unknown

Voltage is too high

get the electric company to take a look. As for transformers a NEMA rated Class II standard DC20-92 transformer (required on all heating equipment) should not have voltage on the secondary higher than 26.5 to 27 volts.

A lot of controls in my experience that see above 125 volts tend to have problems.

RichW

voltage

Are those static or load voltages? You may find that the voltage drops to 24volts under load. If they are load voltages I would contact the power co.(after trying another XFMR).

Good Luck

Unknown

Tom

Normally, we wouldn't want to see anything in excess of 26.5 to 27 volts in a control circuit. Vent dampers (Effikal) as far as I remember, have a high end limitation of 28 volts and Honeywell gas valves max out at around 30 volts. Find out why the primary voltage is so high and get it fixed. We usually see it the other way around or low voltage causing the problems. Hope this helps.

Glenn Stanton

Burnham Hydronics

Rudy

Thanks for the Responses

> Are those static or load voltages? You may find

> that the voltage drops to 24volts under load. If

> they are load voltages I would contact the power

> co.(after trying another XFMR).

>

> Good Luck

Rudy

Thanks for the Responses

The readings are static and dropped to about 26-27 when relay,and damper motor or GV was energized. What got me was the cube relays in the zone panel were unusually loud also (seperate transformer). Not as much load there so voltage only dropped to 27-28. I'm at a loss how to address these issues as it's my equipment that is most affected. I haven't heard back from the GC but I can only assume the utility co. isn't gonna change THEIR transformer becouse of some 'slapping relays'. I'll keep you updated. HO is out of town for a week so I won't be rechecking till then.

Thanks guys,

TG

jim lockard

Suprized

That the HO can keep light bulbs in the home with that voltage. What is your phase to phase voltage? Should be between 230 /240 volts. From what your posting your voltage is running around 255/260 phase to phase thats to high most likly a mis tap or a loose connection on the primary side I would contact the power company. I would do it quickly as the HO will not have any electronics left in the home to play with.God bless regulated power supplys. That voltage will shorten the life of your controls as well. You asked about regulating the power supply with dimmers yes to prove a point you can do that (no motor loads) and do not exceed the rating of the dimmer. The other way to do this is with a buck transformer that will correct the voltage on your end. Still you need to get the Power Company involved. Best Wishes J.Lockard

Brad_3

Power co voltage

I believe that the power co is required to fix their voltage if it goes over 132 per phase. Depending on the person you're dealing with, often they will adjust it if you ask nicely.

jim lockard

Go BIg

The Power company has hear this before. The local Power company here in Va has an instrument that plugs in the meter socket and helps to diagnose problems such as you are describing. Being a new home you could have a hi leg primary service that has been hooked up wrong or any number of other problems. Call the Power Company's help desk describe the problem and request a trouble truck stop by and check the power. Best Wishes J.Lockard

jim lockard

Go BIg

The Power company has hear this before. The local Power company here in Va has an instrument that plugs in the meter socket and helps to diagnose problems such as you are describing. Being a new home you could have a hi leg primary service that has been hooked up wrong or any number of other problems. Call the Power Company's help desk describe the problem and request a trouble truck stop by and check the power. Best Wishes J.Lockard

Rudy

Wow

Just came back from a 14 hr day and am darn glad to hear these responses. You guys are incredible. I didn't do a phase check...just walked around with my meter and did 110V random checks at accessable outlets. As this is warranteed new construction I wasn't about to pull the panel cover and check. That's the electricians job. I may copy this thread and forward it to the GC. IMHO it took a diagnostic by me to discover a larger, lurking culprit. When HO told me about the resistance appliances (iron and coffee pot) going bad the first thing I thought about was "Why not TV or stereo,etc..". Made it tough to fall asleep last night.

Again....I'll keep y'all posted

TG

jim lockard

New work juicers

Most of your new work electricians are walking around with a neon lamp tester and for your problem that will not get it you need a real voltage meter.

Rudy

EMI VOM

Garden variety VOM/amprobe. Yeah you're right most electricians wouldn't know what half the functions are about.

scrook_2

a 128 VAC line

should yield 25.6 VAC output from a 120 V to 24 V transformer.

General rule is utility voltage should be between +10% and -15% (the latter, -15% occuring (hopefully) only occasionally due to brownout conditions) or 102 to 132 for a 120 V nominal and 26.4 to 20.4 for a 24 V nominal.

Can you get the utility to check the supply and perhaps retap their transformer?

Alternately a very small bust/buck transformer could be used to drop the 128 closer to 120 (a 5% reduction would yield 121.6).

Howard

Noisy Relay

If the noisy component is just an isolating relay in the boiler, I'd be tempted to use a sequencer or a time-delay relay that is very quiet. Also I'd check for voltage between neutral and ground at a few outlets and at your equipment. I don't know what the spec is but I'd be concerned with even a volt or two.
Howard Hansen

jim lockard

Well Flange I do not know

About that 128volts X 2 = 256 volts Phase to phase might be a little hard on the A/C unit and the blower motor in the air handler.Soild State Printed circuit board in the boiler is going to hope you have a regulated Xformer for control voltage or she will frying Best Wishes J.Lockard

bigugh_4

Those little

40va xfmrs ! ! ! Most made out of the conntry./ with low paid wage earners. it is a wonder we do not have more of the problems than we have. Look at the brand of xfmer you have and get a new one,(different brand). Even the xfmrs in HW controls are made south of the border. and it takes so little inattention to just let a couple of windings extra go on or off the spool that when making them by the piece, why waste time redoing them. That or a to much wine when winding! I recently went thru 4 xfmrs till I got one that was ok!
bigugh

Don Baker

You can get a phase to phase reading at the range outlet or dryer.

bake

Rudy

transformers

I'd have to defer to the mfg. on this one as the equipment and the new home are still at warrantee status. As posted earlier I was getting high readings from the boiler xfmr AND the zone panel xfmr. I'm going to wait and see what the utility co.'s response is before I start changing parts.

jim lockard

Pull the

Disconnect on the A/C and check it there quick / clean and you will not risk damage or disturbing the home. No one need know. Best wishes J.Lockard

BillW@honeywell

NEMA rated transformers

When I used to get out of the office to do training, I ALWAYS recommended that you use NEMA rated transformers. They will provide the voltage they are supposed to across their rated range. Sure, they cost a buck or two more, but the headaches they eliminate are priceless.

Glenn Harrison_2

Tom, since your dealing with Communist Edison (Com ED)

I'm going to try to save you a little time and aggrivation based on my previous experiences with Com Ed. If you are not a certified, Licensed Electrician, Com Ed is going to give you a hard if not impossible time. However they seem to have no problem listening to licensed electricians. So your best bet is to have the GC's electrician ceritfy the overvoltage and call Com Ed, or hire your own licensed electrician to certify the overvoltage. I say this because I've had three overvoltage situations with Com Ed and the first two the Com Ed rep was basically laughing at me when I said I was an HVAC tech and not an electrician, and the third time they played 20 questions as to who I was and what meter I used and how I tested before sending a Com Ed tech out.

Also, is this a new subdivision new construction? If so you may be out of luck as I've been told Com Ed sizes their transformers for the final house load and if the transformer is loaded minimaly due to a lack of houses being connected the voltage may be and stay high untill more of a load is connected.

Good luck with Communist Edison!

Glenn.