Temperature limitations

[INTELLECTRIC]

Hi:
Looking to meter domestic hot water; temperature should not normally exceed 120 deg.F. While there is the HOT version of the horizontal meter, I don't see a HOT version of the vertical meter, which would be necessary in this installation. The standard vertical meter shows a maximum temperature of 122 deg.F.

I am wondering if there is some buffer space to the 122 deg.F specification that would allow it to perform consistently under all conditions in a domestic hot water system.

Thanks.

[Jameson]

I probably would not risk it to be honest. I would either find an appropriate 3rd party vertical hot water meter model (preferably with a pulse output), or I would use one of our horizontal hot water meters and just plumb it so that the water meter is installed horizontally and the pipes are plumbed to accomodate.

If you have a vertical pipe you want to meter with a horizontal meter you can:

Install a 90 deg elbow from vertical to horizontal.
Run a straight pipe to the input of the water meter.
Exit the water meter with a straight pipe
Install 2 more 90 deg elbows (use a bunch of 45s if you don't want to restrict the flow)
Install a long straight pipe.
Install a 90 deg elbow from horizontal to vertical

Pipe Lengths Rule of Thumb:
Must have at least 10 pipe diameters in pipe length before the water meter and at least 5 pipe diameters in pipe length after the water meter. For example if you have 1.5 inch pipe and water meter you would want 15 inches of straight pipe before your water meter and 7.5 inches of straight pipe after your water meter. This is to achieve maximum accuracy. If the straight pipe length before and after the meter is less than this, the water meter will still be highly accurate, just not as accurate if you follow the above rule of thumb.

3/4” water meter:
Straight pipe must be: 7.5” before meter and 3.75” after meter
1” water meter:
Straight pipe must be: 10” before meter and 5” after meter
1.5” water meter EKM-SPWM-150:
Straight pipe must be: 15” before meter and 7.5” after meter
2” water meter:
Recommended 20" straight pipe before water meter and 10" after.

[johndoe531]

Pipe Lengths Rule of Thumb:
Must have at least 10 pipe diameters in pipe length before the water meter and at least 5 pipe diameters in pipe length after the water meter. For example if you have 1.5 inch pipe and water meter you would want 15 inches of straight pipe before your water meter and 7.5 inches of straight pipe after your water meter. This is to achieve maximum accuracy. If the straight pipe length before and after the meter is less than this, the water meter will still be highly accurate, just not as accurate if you follow the above rule of thumb.

A question about straight-pipe requirements before & after water meters ---

Let's say you need 10 pipe diameters before the meter, for a 3/4" pipe that's about 8" of straight length.

Can you/do you count a union-fitting meter adapter piece as part of that straight length? Or do you need an additional 8" of straight pipe before the meter-adapter union fitting?

Here's a photo of what I mean by "union fitting meter adapter" --- the brass pieces attached at either end of this blue-colored meter.

Let's say you need 8" of straight pipe attached to the inlet of this meter. Do the 2.5" to 3" long brass fittings count as part of that 8" minimum length, or does there need to be an additional 8" of straight pipe before the brass adapter fitting itself?

Screenshot 2025-02-07 at 11.35.07 AM.jpg (71.85 KiB) Viewed 1652 times

[Jameson]

I think you can include the union in the straight pipe part of the calculation.

This is not intended to answer your specific question, but I thought I should include it here as well. The ideal water meter install would have: incoming water > shutoff valve > gravity trap > a sieve or a filter > a check valve > straight pipe > the water meter (installed horizontally) > straight pipe > water hammer arrestor > shut off valve > to water users