Range Powermax 155 replacement with Valliant 38kW combi ?

Hi Mike

Thanks for your site which has been incredibly helpful. I'm replacing an 18yr old Range Powermax 155 with a Vaillant 38kW combi as the old powermax is only delivering 6L/min hot water now and intermittently not firing up for CH. I have read your replacing the powermax guide that says a combi would not match the powermax on hot water, and that the way to go is a vaillant/megaflo unvented cylinder but think this was written a few years ago? and was wondering if one of these 38kW ones would cut it as a replacement?

thanks, mat