I have a 70 gallon tub that takes forever to fill with the single 1/2 hot water line. I have complete access to all the plumbing and I personally ran pex to a distribution center and branched off 1/2 lines to all the fixtures. The cold water in colorado is really cold coming out of our well and thus we can only trickle the cold tap while running the hot tap wide open. It takes 20 min or more to fill the tub.

Looking for suggestions on improving the hot water volume to fill the tub faster.

Can I run a second 1/2 in line and T in just before to the faucet handle?

Should I run a 3/4 in line to just before the faucet handle and then reduce to 1/2?

Should I run a second 1/2in line and add a second fill handle for hot?

Can I run a 1/2 in hot line and T into the cold tap so that the cold at full throttle would actually be warm? I see no need for full cold water in the tub.

Replace the faucet set with a 3/4 in set and run all new 3/4 in lines to them?

Hit me with your ideas.

3/4 all the way should help.

Something I did when building was to use a de-burring tool on the edges of ALL pipe/tubing I was installing. In particular deburring the INSIDE edges. Wish I had done it on everything, got lazy part way through. The pipes that were done have obviously better pressure & volume.

If you use something like shark bite fittings be sure to deburr the outside edges as well. They seal with an O ring and you don’t want a rough edge damaging the ring.

My pipes are 1/2” copper most of the way. Good pressure in those too.

3/4 faucet and lines.
You will likely have to increase your hot water capacity also.

This message has been edited. Last edited by: sunburn,

I agree, 3/4" line would greatly help.

Get your bride a bigger bottle of wine for the fill time?

Tub??? Do we get a giant scrubby-brush too?

70 gallon tub. What size water heater do you have?

What is the smallest diameter pipe coming into your house? If at any point you have 1/2", adding 3/4" after it won't help.

Domestic water booster pump.

We love our 199k BTU tankless unit for hot water.

What is the size of the piping in the faucet...if it’s 1/2” it won’t matter what size piping you put behind it....you can only get x amount of water thru a 1/2” fitting.

quote:

Originally posted by MikeinNC:
What is the size of the piping in the faucet...if it’s 1/2” it won’t matter what size piping you put behind it....you can only get x amount of water thru a 1/2” fitting.

Thanks for the help so far guys. I have a hybrid 80 gallon tank, it's a 'man size' Jacuzzi tub that i use to unwind my body after a long weekend of dirt bike racing.

The pipe run is pex from just below the bathroom in a mechanical room. It's at normal house temperature so there is little heat loss in line. I have the temp set at 124 right now, which is pretty dang hot when it's the only one on.
The cold water at this time of year is under 50, probably closer to 40ish. So a little cold water takes out a lot of the hot water. I don't think I want to up the temp any higher due to kids in the house.

It's a newer tub and faucet set, separate hot and cold,no mixer. I'm pretty sure it's a 1/2 in faucet set, gonna crawl under it later and double check.

quote:

Originally posted by MikeinNC:
What is the size of the piping in the faucet...if it’s 1/2” it won’t matter what size piping you put behind it....you can only get x amount of water thru a 1/2” fitting.

That is really the heart of the matter, if you double the volume to the same 1/2 in restriction do you get more flow or just higher pressure? Do i need a second 1/2 line and faucet or do I need to get a 3/4 faucet set for a bigger line?

Interesting question.

I just went on the Kohler website and found that you can order a 3/4” valve system for some of their tub faucets. If you can run 3/4” pex from your water heater to the faucet this would be a good option.

https://www.us.kohler.com/us/3...58193&brandId=empty&

I would still recommend wrapping the pipe with foam insulation as it will make a difference and pay for itself in short order.

Being the lazy type, I'd start with the simple (but often overlooked ) stuff.
Check the aerator at the nozzle to be sure it is flowing freely.

I'm afraid to say it, but if it is a newer faucet, the faucet is probably the problem.

This message has been edited. Last edited by: wreckdiver,

quote:

That is really the heart of the matter, if you double the volume to the same 1/2 in restriction do you get more flow or just higher pressure? Do i need a second 1/2 line and faucet or do I need to get a 3/4 faucet set for a bigger line?

You can increase the pressure but there is a limit to how much can get thru a 1/2” fitting..

The best bet is to run another line (bigger) and replace the small faucet or add a completely separate faucet.

But if the new run is also restricted by the output of the water heater’s fitting, they are usually 3/4” and of course that will flow more volume.

You could run a 3/4” tee off of the water heater and have one line dedicated to the spa, with a bigger faucet. So that the spa has its own line and that may be sa shorter run for the spa- which is good too, may have less heat loss over a shorter run.

quote:

Originally posted by MikeinNC:

The best bet is to run another line (bigger) and replace the small faucet or add a completely separate faucet.

But if the new run is also restricted by the output of the water heater’s fitting, they are usually 3/4” and of course that will flow more volume.

You could run a 3/4” tee off of the water heater and have one line dedicated to the spa, with a bigger faucet. So that the spa has its own line and that may be sa shorter run for the spa- which is good too, may have less heat loss over a shorter run.

Yes, that's the plan so far. I'm going to start cheapest and work my way up. First step will be to add a second 1/2in line t'd into the cold line to make it warm. If that doesn't work I will T off the 3/4 in hot water line and see if I can add a single faucet. If that doesn't work I will upgrade the whole set to 3/4in.

quote:

Originally posted by jeffxjet:

quote:

Originally posted by MikeinNC:

The best bet is to run another line (bigger) and replace the small faucet or add a completely separate faucet.

But if the new run is also restricted by the output of the water heater’s fitting, they are usually 3/4” and of course that will flow more volume.

You could run a 3/4” tee off of the water heater and have one line dedicated to the spa, with a bigger faucet. So that the spa has its own line and that may be sa shorter run for the spa- which is good too, may have less heat loss over a shorter run.

Yes, that's the plan so far. I'm going to start cheapest and work my way up. First step will be to add a second 1/2in line t'd into the cold line to make it warm. If that doesn't work I will T off the 3/4 in hot water line and see if I can add a single faucet. If that doesn't work I will upgrade the whole set to 3/4in.

I would not T a hot line into the cold line. You can back feed the cold into the hot water tank or any other source of issues.

What you can do, is put one of those small electric instant hot water heaters designed for under a sink inline on that cold and it should warm the cold side up a bit. OR, run the 1/2" additional hot line parallel to the other 1/2" hot and T it to the hot at the faucet to get more flow.

quote:

Originally posted by jimmy123x:

I would not T a hot line into the cold line. You can back feed the cold into the hot water tank or any other source of issues.

I've got to get some check valves for a different problem so I would add one here as well.

quote:

Originally posted by jeffxjet:

quote:

Originally posted by jimmy123x:

I would not T a hot line into the cold line. You can back feed the cold into the hot water tank or any other source of issues.

I've got to get some check valves for a different problem so I would add one here as well.

I think you're better off running a dedicated 3/4" line all of the way to the hot.

Hi jeffxjet,

I am just down the road in Kiowa...

If you are on well water, I would check first for sand and sediment in the system. We discovered when we had some plumbing work done that the aerators and screens and lines had sand, rust and sediment that was causing slowness to most of the taps throughout the house.

An Aquapure sediment filter installed by a good plumber was the first piece in the fix. That said, we have 3/4" or 1" all the way through the filter and to a laundry tub with a high flow Kohler faucet to give great flow rate for filling buckets for the critters during the winter when the hoses freeze... It was worth every dime to have the dedicated plumbing installed for the laundry tub.

We found that the rest of the house had greatly reduced problems due to the filter - no more sediment in the lines to the washer, consistent flow to the "water saver" shower heads. The rest of the house has more narrow piping and some with Pex.

You might consider having a plumber run a dedicated 3/4" lines to your tub with the right size of faucet to prevent flow restriction as earlier posts mentioned.

Good luck and hope you get a fix.
Kevin

I had a similar problem in a jacuzzi tub / shower combo years ago in a house I owned. A set of "fast fill" faucets completely fixed the problem.

I added them below, and in addition to, the single handle unit mounted mid height that fed the shower head and tub both originally. I hooked the tub only to the new set, leaving the original set, a nice set, for the shower. It worked beautifully and reduced the fill time to about 1/4. That tub was fed by 1/2 inch pipe at ~60 PSI.