Watts Valves, Recirculating Pumps, and the Repair Parts I've Wasted Money On

Eight years ago, I started ordering parts for a small commercial building-services company. I'm the maintenance purchasing guy, and I've personally made (and documented) 14 significant mistakes totaling about $5,300 in wasted budget. Now I keep our team's pre-order checklist. This FAQ answers the questions I get from tenants, contractors, and small shop owners. Jump to whatever you need.

• What does a Watts hot water recirculating pump actually do?
• Are Watts valves better than generic valves?
• Can Watts valves replace 80 gallon air compressor parts?
• How do I know if it's a water pump repair or the pump itself?
• Do Watts repair kits work on older valves?
• What welding machine for aluminum should I buy?
• The question you didn't ask: why is the new pump still not working?

What does a Watts hot water recirculating pump actually do?

A recirculating pump keeps hot water moving through a loop so you don't wait for warm water at the faucet. It pushes cooler water in the hot line back to the water heater through a return line. In a building with long pipe runs, that means quicker hot water and less wasted water.

According to Watts (watts.com), a recirculating pump is part of a water-saving system: you get hot water faster and you don't let gallons run down the drain while you wait. As of January 2025, a typical 3/4-inch Watts small circulator is somewhere in the $120–350 range depending on the kit and controls (based on dealer quotes; verify current pricing).

My first mistake with one was in 2017. I assumed a stronger pump would fix a slow hot-water complaint. The old pump was making weird noises, but the real problem was a stuck check valve. The new pump couldn't fix a blocked loop. That lesson cost me two attempted pumps, one return, and about $680 of wasted budget.

Are Watts valves better than generic valves?

Better is the wrong word. Depends on service. I've installed Watts pressure reducing valves, check valves, relief valves, and mixing valves for years. The main reason I keep a few on hand is that Watts publishes specs and sells repair kits. When a valve fails, I can often rebuild it instead of sweating in a new one.

For non-critical shut-off duty, a generic ball valve is fine. But for anything protecting people or property—pressure relief, backflow prevention, water temperature mixing—I buy Watts or an equivalent code-listed brand. A 3/4-inch Watts pressure reducing valve is around $50–130, and a small pressure relief valve is around $15–60 (based on dealer quotes, January 2025; verify prices).

Here's the thing: the valve brand matters less than the valve being rated for the actual pressure, temperature, and fluid. The logo is not the safety device. Installing a cheap relief valve because it has the same thread size is how bad things happen.

Can Watts valves replace 80 gallon air compressor parts?

This one surprised me when I first started ordering air compressor parts. A lot of the key parts on an 80-gallon air compressor are valves. The tank relief valve, the check valve in the discharge line, and sometimes the unloader valve are all normally available from valve manufacturers, including Watts.

But don't get too creative. A plumbing pressure reducing valve is not an air pressure regulator. Water valves and air valves have different pressure ratings, and compressed air needs valves with the right orifice size and discharge capacity. For an 80-gallon tank, the required relief valve capacity is stamped on the tank's nameplate. Match that exactly.

In March 2021, I had about 20 minutes to pick a relief valve before our freight order closed. I matched the thread size but not the rated capacity. The valve arrived, and it was too small for the tank's stamped CFM requirement. $240 in shipping and restocking fees later, my rule became: nameplate first, catalog second, order after that. Period.

How do I know if it's a water pump repair or the pump itself?

If someone searches for water pump repair, they usually have a circulator pump on a heating or hot water recirculation loop. The pump starts making noise, leaking, or simply not circulating. Before you order a replacement, check four things:

• Power and voltage rating: I've ordered a 115V circulator for a 230V panel, then had to return it.
• Check valve function: a stuck check valve can stop flow even with a new pump.
• Impeller movement: on pumps that have been sitting, the impeller can freeze with scale.
• Bearing noise: a grinding bearing can sound like a pump failure but the motor bearings are the actual issue.

For many Watts circulators, you can buy a repair kit instead of a whole pump. In Q4 2024, I fixed a 3/4-inch unit with a $35 repair kit instead of the $220 replacement pump. That's the water pump repair I like: small order, small cost, same result.

Do Watts repair kits work on older valves?

Usually, yes, if the valve body is in decent shape. A repair kit for a pressure reducing valve or check valve replaces the diaphragm, washer, spring, or seat disc. I've rebuilt 20-year-old Watts valves that worked like new afterward.

But a repair kit doesn't fix a corroded body or a bad seat. In September 2022, I ordered a mixing valve repair kit without opening the valve first. The outside looked fine; the inside was full of scale and the body had stress cracks around the threads. The $48 kit should have been a $180 valve replacement. I ended up buying the valve anyway and cleaning up a flooded utility closet.

My current rule: if the valve looks old or has visible corrosion, order the repair kit and the complete valve at the same time. Return the one you don't need. It's a bit of a nuisance, but it's cheaper than a second freight charge and a 3-day delay.

What welding machine for aluminum should I buy?

This isn't a Watts part question, but I get it constantly when I tell people about compressor repairs and pipe jobs. So here's the short answer:

For aluminum up to about 3/16-inch thick, an AC/DC TIG welder with high-frequency start is a solid all-around choice. AC current is what breaks up the oxide layer on aluminum, so DC-only TIG is not what you want. For thicker aluminum, 1/4-inch and up, MIG with a spool gun or push-pull system is faster.

If you only weld occasionally, I'd buy a 200-amp class AC/DC TIG machine. You can weld steel, stainless, and aluminum with the same unit. In 2018, I bought a DC-only TIG because it was $300 cheaper. It worked great on steel. It was useless for aluminum. I sold it at a loss and bought the AC machine.

Ask a local welding supplier to let you try the machine on a piece of 1/8-inch aluminum before you buy. Also check the input power and duty cycle. A small compressor might not power a high-amp welder, but that's another FAQ.

The question you didn't ask: Why is the new pump still not working?

This one caught me in 2020. We replaced a Watts hot water recirculating pump on an apartment loop, and the tenant still had no hot water. The pump was fine. The check valve at the end of the loop was stuck shut, so the pump was dead-heading against a closed line. A pressure gauge showed the problem in five minutes.

A pump can't create flow if the loop is blocked. The same logic applies to air compressor repairs: a new relief valve won't fix a tank that won't hold air if the check valve is leaking backward. Check the whole path, not just the part with the warning light.

Now I use a simple pre-order checklist: confirm symptom, test the check valve, verify the model number, look for a repair kit, then order. In the past 18 months, that checklist has caught 47 potential errors. Most of them were on small orders from smaller maintenance shops. That's the point.

Small doesn't mean unimportant. When I was starting out, the suppliers who treated my $200 orders with respect are the ones I still call for $20,000 orders.