Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.
New RU199iN (199k BTU) delivering just around 161k BTU
natural_gas_src
Member Posts: 5
Hello all,
I recently hired a plumber to install a Rinnai Tankless RU199iN. The heater seems to be functioning as expected, but it isn't delivering hot water at the maximum flow rate stated in the specifications.
According to the system’s specifications, the heater should be able to output hot water at 5 GPM (∆T=75F; with incoming water at 45F and set temperature at 120F). However, the peak capacity I currently observe is only 4.3 GPM, which is around 161k BTU.
To rule out water flow restriction, I changed water pressure to 50psi and 80psi from 60psi (my normal water pressure) by adjusting the PRV.
I measured the maximum flow rate. It remains the same at 4.3GPM at both 50psi, 60psi & 80psi.
I also noticed the water flow control servo is in mid position instead of being fully opened using the diagnostic menu when the heater is giving out 4.3gpm of hot water.
(Additional data: HX tempature is at 142F, bypass value is at 30°).
I suspect the issue may be related to gas supply rather than water supply.
The gas pressure measurements are as follows:
- Static gas pressure at 6.6" WC
- Full load gas pressure at 5.3" WC
They fall within the range of the required gas pressure (3.5" - 10.5" WC). However, these readings tend towards the lower end of the range.
Could it be the reason why my water heater is giving out less hot water? What's the easiest way to unleash the full power of my water heater?
Thank you.
I recently hired a plumber to install a Rinnai Tankless RU199iN. The heater seems to be functioning as expected, but it isn't delivering hot water at the maximum flow rate stated in the specifications.
According to the system’s specifications, the heater should be able to output hot water at 5 GPM (∆T=75F; with incoming water at 45F and set temperature at 120F). However, the peak capacity I currently observe is only 4.3 GPM, which is around 161k BTU.
To rule out water flow restriction, I changed water pressure to 50psi and 80psi from 60psi (my normal water pressure) by adjusting the PRV.
I measured the maximum flow rate. It remains the same at 4.3GPM at both 50psi, 60psi & 80psi.
I also noticed the water flow control servo is in mid position instead of being fully opened using the diagnostic menu when the heater is giving out 4.3gpm of hot water.
(Additional data: HX tempature is at 142F, bypass value is at 30°).
I suspect the issue may be related to gas supply rather than water supply.
The gas pressure measurements are as follows:
- Static gas pressure at 6.6" WC
- Full load gas pressure at 5.3" WC
They fall within the range of the required gas pressure (3.5" - 10.5" WC). However, these readings tend towards the lower end of the range.
Could it be the reason why my water heater is giving out less hot water? What's the easiest way to unleash the full power of my water heater?
Thank you.
0
Comments
-
-
Thanks. I will call my gas company and Rinnai and post an update later. I apologize for the double post. I could not delete the duplicate.0
-
-
-
My house is located at 800 ft.PC7060 said:Are you located above 4500 ft elevation?
I used the Rinnai's built in diagnostic menu to measure the flow rate. To find out the maximum flow rate, I turned on all the faucets (2x bath, 1x shower, 7x sinks) at the same time.hot_rod said:How are you measuring the 4.3 gpm?
0
Categories
- All Categories
- 86.3K THE MAIN WALL
- 3.1K A-C, Heat Pumps & Refrigeration
- 53 Biomass
- 422 Carbon Monoxide Awareness
- 90 Chimneys & Flues
- 2K Domestic Hot Water
- 5.4K Gas Heating
- 100 Geothermal
- 156 Indoor-Air Quality
- 3.4K Oil Heating
- 63 Pipe Deterioration
- 916 Plumbing
- 6K Radiant Heating
- 381 Solar
- 14.9K Strictly Steam
- 3.3K Thermostats and Controls
- 54 Water Quality
- 41 Industry Classes
- 47 Job Opportunities
- 17 Recall Announcements