What Do You Know About Recirculating Pumps? (Prevent Frozen Pipes)

[DerbyDad03]

I spoke to a rep at the vendor. He said that the $299 "under the sink" pump should work just fine for this situation. Extended periods of sub-freezing temps will not kill the pump. It's designed to run 3 - 4 times an hour for a couple of minutes for many years. I believe the specs are on at 84°F, off at 104°F.

84°F at the pump is a long way from the 20°F burst threshold that the crawl space pipes would need to get down to. They are insulated, so that will help.

Depending on how the house is plumbed, it may just move water in that single loop or it may provide instant hot water at other fixtures. Essentially, it's going to circulate water from wherever it is installed all the way back to the water heater. In this house, the powder room is T'd off the pipes to the washer and the washer is in the room right next to the water heater. WH---Washer---Powder Room. If it's plumbed as simple as that, it'll just do that loop.

We agreed that if the house deal goes through and I have a better idea of how the house is plumbed, I will call back and maybe send them a diagram so he can make a definitive recommendation as to which system to use and how/where to install it.

A $300-ish "plug and play" solution is an easy trigger to pull vs. turning off the water all winter or the heat tape/light bulbs/extra insulation crawl space methods.

[whit3rd]

Alas, that doesn't work.

Insulation in my clothing protects me from cold, but I'm alive and generate body heat.

The water does not have a heat source, so insulation will change the RATE at which the pipes freeze (might work for a four-hour cold snap) but that doesn't solve the problem of a week-long hard freeze. A basement has lots (tons) of concrete and soil which is reliably over freezing in temperate climes, so heated or not, pipes there usually don't freeze.

Heat tape is the easy solution, and the product hasn't let me down yet. One could, I suppose, do other things, but are pumps more reliable than wire and a thermal switch?

[whit3rd]

Make that $600-ish; don't you have both hot and cold plumbed to the 'powder room'?

[dpb]

...

The heat source is the heated house above it...as another went on to expound on.

--

[DerbyDad03]

Perhaps you didn't look at the links I provided.

The pumps we are discussing are actually a pump and crossover valve in one under- the-sink unit or a pump at the water heater and a cross over valve under the sink. The choice depends on whether there is power available under the sink or not.

The pump pulls hot water from the water heater into the hot water pipe and pushes it through the cross over valve into the cold water pipe and back to the heater.

AMH3K-7 (requires power under sink)

AMH1K-3UV (does not required power under sink)

(I actually have an weird "automatic" system like that in my house. I have both hot and cold water hose bibs at the front of the house. The cold bib is plumbed before the PRV and the hot is obviously after the PRV. I have a Y hose that connects the bibs to the garden hose. When I turn on both bibs and leave the garden hose closed, the higher pressure cold water pushes the hot water back into the in-house plumbing. That results in lukewarm water at both the hot and cold taps throughout my house, warm water at the toilets, etc.)

[Leon]

Thoughts on keeping the toilet boll from freezing?

[G Ross]

1- Keep the door open 2- Antifreeze in the bowl (and tank).

[DerbyDad03]

I assume you mean the toilet bowl supply line. No reason that the bowl itself would freeze, it's inside the conditioned space.

That has been on my mind and certainly something that will need to be looked at and rectified if need be. The toilet is opposite the vanity, on the kitchen side of the powder room, while the vanity is on the exterior wall. Maybe we'll get lucky and find that the toilet is plumbed from the kitchen, which *might* mean no supply pipe in the crawl space.

That's all TBD.

[J. Clarke]

I think you're missing the concept. You don't want either pipe to freeze, that means that you need hot water going through the cold pipe. So it comes in through the hot pipe and returns through the cold one. You need some cleverness with the valving to have the cold tap still provide cold when wanted--you'll have to run the cold for a bit to get the hot water out instead of the other way around.

[Leon]

Which might be cool if you like sharing your deposit. And or adding antifreeze after every flush. ;~)

[Leon]

Well not knowing all of the circumstances in a 20's something home, the insulation may be nonexistent. The space may be as likely to be conditioned by outside temperatures as inside temperatures if the door is kept close after a stinky one late one night. (:~0)

[DerbyDad03]

Well, not that it makes that much of a difference, but updated info indicates that the house was born in 1935, not in the 20's. We don't know when the porch was converted to a powder room but it sure doesn't look 85 YO. ;-)

Anyway, I was looking at some pictures of the interior today. Based on the layout of the kitchen and powder room, it looks like it might be possible to bring the supply lines up from the basement into a kitchen cabinet, then through the former exterior back wall into the powder room.

A less than 4" x 4" enclosure along the base of one wall in the powder room could house the pipes, meaning that they would be *in* the bathroom instead of under it.

Other than another surface to dust, not much maintenance with that solution. ;-)

[Clare Snyder]

Insulate a "box" around the pipes and open it to the warmer basement and the pipes will NOT freeze

[Leon]

Ah! That sounds like a better plan.

[DerbyDad03]

Well, we'll find out soon enough. The offer has been accepted and the closing is scheduled for November 30th.

The house is empty so the buyer has asked the seller's realtor to see if we can get in over the Thanksgiving weekend, even if it's just to do a top to bottom cleaning. It would suck to lose those 4 days when a whole bunch of us are available.

[DerbyDad03]

Well. that was a bust.

[DerbyDad03]

Well, that was a bust.

The seller's atty advised against letting the buyer in the empty house before closing.

Instead of having a few days to clean and maybe move in on Sunday, nothing can done until after the closing on Monday afternoon. That pushes the move into December, resulting in another month's rent at the buyer's current apt.

Darn!

[krw]

Offer the seller rent until closing? Since it's only a few days and you'd avoid a month's rent, you can make it rather attractive for them. Both sides can win here.

[DerbyDad03]

Yeah...the move on Sunday and getting out of the apt by the 1st was a long shot anyway. There's a room mate involved, cleaning the apt, etc.

Our current plan is to spend the week of the 30th cleaning the still empty house, hopefully address the plumbing issue, do some lite electrical work, remove some old carpet, etc. We'll have more bodies on the weekend of the 4th for the full move.

The basement reminds me of my house when I moved in 35+ years ago. A switch in the kitchen turns on a single fixture at the bottom of the stairs and then there's 3 or 4 pull chain fixtures spread out around the basement. A few feet of Romex and a couple of hours of work and the switch will light up the whole basement. [He says confidently from a 165 miles away. ;-) ]

[Unquestionably Confused]

Sorry to be late to this party, but I believe I have the PERFECT answer to your problem.

I saw this first on "This Old House" or "Ask This Old House" where it was highlighted by everybody's favorite plumber, Rich Trethewy.

Get yourself a Watts Recirculating Pump. No need for additional wiring, mucking about in a crawl space, etc. If you have access to that powder room sink and your water heater, you're golden!

OR

Simple installation. The transfer valve mounts underneath the sink in the powder room and the pump near the water heater. If you wish, multiple valves can be placed in sinks a further distance away. The benefit of this (and the main purpose of the pump) is to eliminate the need for you to run the hot water at a sink or bath in order to get warm/hot water flowing.

The pump has three settings: On, Off or Timed. The way it works is the pump provides a constant trickle flow to the transfer valve which then backfeeds the warm water to the cold line. I'm not a fluid dynamics exspurt but the damn thing works. In most installations you would just place a single transfer valve at the sink furthest away from the hot water heater, but if you have a leg or two (like you do) that's more or less all by itself, then consider an additional valve.

It's really nice to turn on a lavatory tap or shower and have hot water almost instantly instead of waiting for it. The only "downside" that my wife complains of is that when you turn on the cold water, it's actually a bit tepid for the first 20 second before the ambient temp of the cold water is available.

I installed this about eight years ago and it's functioned perfectly with zero maintenance issues. Install was easy peasy!