Grundfos pump dont seem to work for hot water?

rx7ven

I have this grundfos pump i bought from home depot
https://www.homedepot.com/p/Grundfos-UP15-10SU7P-TLC-3-4-in-NPT-115-Volt-Comfort-Hot-Water-Recirculation-Pump-595916/302859594?cm_mmc=ecc-_-THD_ORDER_CONFIRMATION_BOSS_STH-_-V1_M1_CA-_-Product_URL&ecc_ord=WE15052882&em_id=84f9caddc43fdf43ff83d9160be4a591ba3a2e612ab7505d39895d8267080262

The pump is brand new and installed by my contractor when i remodeled the house. Everything looks to be installed correctly. The water heater hot water line goes to the pump and then into the wall. The comfort valve is installed in the farthest bathroom in the guest bath. But in the master bath where i use it, it still takes around 30+ seconds to get hot water. If i dont turn on the pump, it takes around 40 seconds, so i think it seems to work? but from what I read online, and the reason why i bought it is, i'm supposed to get hot water within 10 seconds.

How long do i typically need to run the pump before theres hot water? i usually run it 15 min to 30 minutes before i hop in the shower. Do i need to install another comfort valve under the master bath sink?

yellowdog

It all depends on how the house is plumbed, and all the pipes are all probably buried so you will never know. If I didn't want to wait for hot water in one certain bathroom, that is where I would have installed the comfort valve.

dko

You can install additional comfort valves. Does the guest bath get the hot water quickly?
How long is the run and size of pipe from the water heater to the guest bath and to the master bath?

Also what kind of water heater, standard tank or tankless?

Zman

The downside of that setup is that need to wait for the cold water to get cold. It just bleeds the hot water into the cold line giving you delicious luke warm tap water

EdTheHeaterMan

The best Hot Water Recirculation design is before the walls are finished. That is when you can install a dedicated return pipe to the water heater from the farthest hot water tap. You can not be sure that the guest bathroom is the farthest tap away just because it is the farthest walking distance. The hot water pipe may pass the master bathroom before it goes to the guest bath, but it may not. If the master bath is connected to a main pipe that is locates in the basement then there is a substantial run of hot water pipe that dues not have the benefit of the system you have.