ERV balancing (balance chart says Pa, but my meter says kPa)?

[cbednarczyk]

Hi I have a Panasonic Intellibalance 100 FV-10vEC2 I was reading the service manual and it has a balancing chart on page 14. The chart says for unit of measure Differential pressure (Pa) so for 50 CFM the Fresh air side for my unit should be 35 Pa. My question is the meter I was looking to purchase to do the balancing says: Manometer is a professional instrument to measure gauge & differential pressure in the ranges kPa, psi, kgfcm2, ozin2, bar, mbar, inHg, mmHg, inH2O, ftH2O, cmH2O

Is the service manual saying 35 Pa, therefore I need a meter that can measure in single units (not kPa?) is that meter im looking at buying not sensitive enough or is the service manual wrong and it means kPa?

Background:
I measured the CFM of the ERV, and exhaust is like 65-70 CFM no matter what I set those knobs to (50cfm - 100cfm) but supply air can be 80 - 150 CFM. So my guess is the unit isn't balanced at all and im not sure what those knobs do if the CFM rate actually coming out of the unit isn't anywhere close to what the setting is ( one would expect 50 cfm=50 cfm). I have the ERV ducted to the return side of the main hvac ducts.

I have been having humidity issues when the erv is running when its 80 - 100 percent humidity outside, it can go 60 - 70 percent in my home. I basically have to turn it off when it gets that high out and I had to set to lowest settings 50cfm supply, 50 cfm exhaust and only 10 mins per hour.

[teddy bear]

If you are going to have proper air change rate, you will need supplemental dehumidification for the times that the outdoor dew point is above the desired dew point. At 75^F, 50%RH, a 55 dew points, inside air being blown out of the home, the fresh air coming into the home with outdoor at 75^F, 90% RH, a 73^F dew point, expect 75^F, 75%RH, after a couple 3 air changes. Evenings and rainy days require the supplemental dehumidification because the a/c is not running enough.

A small whole house dehumidifier like the Ultra-Aire 70 connected to the a/c will maintain the desired 50%RH when the a/c is not running enough and outdoor is high humidity.
This well worth the effort to clean pollutant free, dry, oxygen rich indoor air throughout the home. Proper installation, correct setup of the a/c, and getting all the connections in the right spot are also important.

Keep us posted.

Regards Teddy Bear

[cbednarczyk]

If you are going to have proper air change rate, you will need supplemental dehumidification for the times that the outdoor dew point is above the desired dew point. At 75^F, 50%RH, a 55 dew points, inside air being blown out of the home, the fresh air coming into the home with outdoor at 75^F, 90% RH, a 73^F dew point, expect 75^F, 75%RH, after a couple 3 air changes. Evenings and rainy days require the supplemental dehumidification because the a/c is not running enough.

A small whole house dehumidifier like the Ultra-Aire 70 connected to the a/c will maintain the desired 50%RH when the a/c is not running enough and outdoor is high humidity.
This well worth the effort to clean pollutant free, dry, oxygen rich indoor air throughout the home. Proper installation, correct setup of the a/c, and getting all the connections in the right spot are also important.

Keep us posted.

Regards Teddy Bear

Thank you, I live in maryland and the humidity outside in the summer seems to be 60 - 95 percent on a regular basis. Humidity in my home is almost always averaging around 55 - 63 percent with a/c running its just cold wet air.
Overview of my setup: Daikin VRV Life 4 ton, house is 3600 sq feet with the finished basement. I have 3 floors total including the basement.
I had the house attic top plates and penetrations sealed and added insulation to get it up to R49. I also had ducting return and supply vents Aerosealed. My last blower door test was 1280, down from 2080 when it was initially tested. I noticed once that top floor was sealed it would get really stuffy in the house especially at night when the a/c stopped running. That is why I had the ERV installed. Since then I did notice humidity gets bad but the house doesn't feel stuffy anymore.
The ERV was installed with both runs going into the return ducts. air is exhausted from further up in the duct, and fresh air goes in right before the filter in the HVAC return.
I dont think its balanced (would that also cause humidity to be higher since exhaust air would be drastically less then supply air it would recover energy from?)

I was looking at Santa fe ultra 120V. here is a few questions about that: 1. If I install it in hvac ducting should intake to the dehumidifier unit come from return hvac ducts and dehumidified air go into supply? Or just have both to return?

One last question: if I am trying to balance this ERV through dampers on the supply air ducting it says to measure from the ports 35 Pa... but the meters I see all say kPa... do I simply have to find one that measures kPa to x.xxx places? x.035 would be 35 Pa on a Kpa meter or no?

Thank you for your insight.

[cbednarczyk]

Would it also make sense to T off the fresh air intake to the dehumidifier (keep separate fresh air from the ERV into the hvac ducting, or put the fresh air port from the ERV directly into the dehumidifier? Or just not have fresh air port used on the 120v?

[teddy bear]

Thank you, I live in maryland and the humidity outside in the summer seems to be 60 - 95 percent on a regular basis. Humidity in my home is almost always averaging around 55 - 63 percent with a/c running its just cold wet air.

[B] You should become familiar with dew point verses %RH. Dew point is a way to express the amount of moisture in the air. %RH is the expression how saturated the the air is at the specific temperature. Outside air at 90^F, 50% RH cooled to 72^F is 100%RH. the dew point is 72^F. 100 cfm of fresh air for a hour requires 4 lbs. of dehumidification keep a home at 75^F, 50%RH, a 55^F dew point. Your a/c needs an air flow adjustment to make it remove more moisture during peak cooling loads. Slow the air flow through the cooling coil to provide a dew point reduction as the air passes through the cooling coil. After several hours of high cooling loads, the indoor %RH should be lower than 50%RH with a proper a/c setup.

Overview of my setup: Daikin VRV Life 4 ton, house is 3600 sq feet with the finished basement. I have 3 floors total including the basement.
I had the house attic top plates and penetrations sealed and added insulation to get it up to R49. I also had ducting return and supply vents Aerosealed. My last blower door test was 1280, down from 2080 when it was initially tested. I noticed once that top floor was sealed it would get really stuffy in the house especially at night when the a/c stopped running. That is why I had the ERV installed. Since then I did notice humidity gets bad but the house doesn't feel stuffy anymore.
The ERV was installed with both runs going into the return ducts. air is exhausted from further up in the duct, and fresh air goes in right before the filter in the HVAC return.
I dont think its balanced (would that also cause humidity to be higher since exhaust air would be drastically less then supply air it would recover energy from?)



I was looking at Santa fe ultra 120V. here is a few questions about that: 1. If I install it in hvac ducting should intake to the dehumidifier unit come from return hvac ducts and dehumidified air go into supply? Or just have both to return?

The Santa Fe Ultra 120V is a good choice. The dehu supply should connect to the a/c supply duct going to the home. Best to connect the dehu return to the open part of the home. Is your a/c blower VS or are you running the blower on normal speed while running the the ERV?

One last question: if I am trying to balance this ERV through dampers on the supply air ducting it says to measure from the ports 35 Pa... but the meters I see all say kPa... do I simply have to find one that measures kPa to x.xxx places? x.035 would be 35 Pa on a Kpa meter or no?

This sounds normal. If the specification is to adjust the dampers for similar pressure at the dampers, you can use your meter.

Thank you for your insight.

I left a few issues that need a response from you.

Keep us posted on the results.

Regards Teddy Bear

[cbednarczyk]

The a/c fan is variable speed, Daikin one thermostat has a "circulate air" function that keeps it running all the time. It does have option to over ride auto with low med high.

Specifically regarding the meter... if it says kPa as a measurement on the meter, but the service manual says 35 Pa, and meter can measure down to two decimal... x.xx 35 Pa is what in kPa? 0.03? so you would have to find a meter that can measure down to 0.035? I don't understand enough about how Pa is measured so its a bit confusing.

[Juan Madera]

I prefer to use an old fashioned Magnahelic for this. Kinda an old fashioned Analog guy I guess.

[teddy bear]

The a/c fan is variable speed, Daikin one thermostat has a "circulate air" function that keeps it running all the time. It does have option to over ride auto with low med high.

Specifically regarding the meter... if it says kPa as a measurement on the meter, but the service manual says 35 Pa, and meter can measure down to two decimal... x.xx 35 Pa is what in kPa? 0.03? so you would have to find a meter that can measure down to 0.035? I don't understand enough about how Pa is measured so its a bit confusing.

What are readings on the pressure reading at the monitoring ports of the ERV?

Regards Teddy Bear