# Frequently Asked Questions

Click on a question below to see the answer.

What is the GPM when the valve is closed?

When Circuit Solver is closed it does not shut off completely and still allows a fraction of a gallon per minute flow. This allows it to better sample upstream water temperature changes, as well as better facilitate high temperature sanitizing cycles of the domestic hot water system.

What is the full open flow rate of Circuit Solver?

The published Cv flow coefficient for each valve size allows calculation of the full open flow rate. Multiply the square root of the pressure differential across the valve by the Cv to get GPM. For example, if pressure differential is 4 psi, square root of 4 is 2, and 2 X Cv = the full open GPM.

What is the highest temperature Circuit Solver can handle?

Circuit Solver can easily handle more than 212F which is the boiling point of water and higher than any water temperature in a domestic hot water system.

Is Circuit Solver certified to NSF 61 or California AB1953 requirements?

Circuit Solver product line was tested by IAPMO R&T and they provided a report confirming that it is fully certified to both ANSI/NSF 61-2012 and California AB1953.

What warranty is offered with the valve? What is the life-cycle?

The Circuit Solver product line offers a 3 year warranty. For many years there have been tens of thousands of mixing valves used in domestic hot water systems and these mixing valves have the same type of actuator as Circuit Solver. These mixing valves generally perform very well and have a proven history of reliability. In fact, since Circuit Solver is all stainless steel it can be expected to perform even better than these valves which are generally brass.

I need to flush and sanitize my lines, will Circuit Solver be able to handle the high temperatures?

Yes. Circuit Solver can handle more than the highest water temperatures that will ever be encountered in domestic hot water systems.

My lines are prone to calcium buildup, will Circuit Solver clog?

The actuator in Circuit Solver is powerful enough that when it modulates, it can force out any buildup in its path. The actuator develops over 40 lbs. of thrust which is more than enough to break loose any mineral buildup. It is also important to keep in mind that the mineral buildup is not very likely to occur in Circuit Solver since it mostly occurs where there is a heating surface or very small leak.

Do I need to use a strainer with Circuit Solver?

In general, No. Since it is used in potable water systems, particles in the water should already be taken care of. If there is a history of particulates causing problems in the domestic hot water system then a strainer is recommended.

What materials are used to produce Circuit Solver?

Circuit Solver is made entirely of Stainless Steel. The valve has been tested by IAPMO to confirm that it contains zero lead or other toxins, and that it complies with the NSF 61 Section 8 Standard; Section 8 specifically applies to “Mechanical Devices such as filters, valves, pumps…”

Does Circuit Solver have any professional certifications?

Circuit Solver has been tested by IAPMO to comply with NSF 61 as stated in IAPMO Report Number 1483-11001. Circuit Solver is certified to NSF/ANSI 61-2012 and California AB1953 requirements..

How do you size Circuit Solver for the recirculation system?

Since the flow through Circuit Solver only has to be enough to offset heat loss in piping, which is typically a very low flow, we recommend using valves that are the same size as the recirculation line.

How do you select the correct setpoint for Circuit Solver?

As described in the product bulletin, the “XXX” in the model number is the desired return temperature. For example if the return temp is 110°F and line size is ¾”, use CS-¾-110

How do you size the recirculation pump when using Circuit Solver?

Use the industry standard plumbing engineering guidelines, for example, as shown in the ASHRAE handbook. There is no need to oversize the pump to compensate for other factors.

Are there existing installations were this Circuit Solver is working?

Yes, please view our “Installations” page to see where Circuit Solver is currently installed.

Does Circuit Solver shut off tightly?

No, there is a small leakage (about 0.1 to ¼ GPM depending on valve size) built into Circuit Solver even when “closed”. This is done so the distribution branches are not totally dead ended. Also, in some applications where the water distribution piping is occasionally chemically or thermally sterilized the leakage allows enough of this flow through all parts of the system to accomplish the cleaning, regardless of temperature.

How do you recommend installing Circuit Solver?

As shown on the product bulletin, there should always be unions and shut off valves installed ahead of and after each Circuit Solver. This provides more convenient access to the valve for future service. Since the water is almost always filtered/strained earlier in the loop, the addition of a strainer ahead of Circuit Solver would be redundant. If no other strainer is present, consider installing one by each valve.

How much does it cost?

When factoring in the labor it takes to manually balance a system and initial cost of balancing valves, Circuit Solver provides significant savings over traditional methods. Contact a sales representative for pricing and delivery.